# August 2010 Archives

## 7th Grade Math - Numbers and Patterns

Patterns are all around us. Whether it is a tile design on a floor or a series of numbers, you'll find patterns everywhere. Unsurprisingly, they occur often in mathematics. In today's free 7th grade math video, we start from the beginning and take a look at some of the first lessons in the course. Today's lectures cover Numbers and Patterns. This concept is not always about adding and dividing. Instead patterns are about looking and seeing. You need to be able to look at a group of things and see the pattern in them. Once you are able to see the pattern, you can often use this knowledge to predict things. This will become useful as you progress in mathematics and touch on topics where you need to predict outcomes.

I love patterns. Determining a pattern can take sharp eyes and a strong sense of logic. It's the logic part I enjoy. Many mathematicians are inspired by patterns, a favorite subject being Fibonacci sequences. A Fibonacci sequence is a pattern where the first two numbers are 0 and 1, and each subsequent number is the sum of the previous two. Search the Internet and you'll find art utilizing this concept and even explanations about how this sequence occurs in nature. Take a look at the flowering of an artichoke, or the arrangement of a pine cone and you are looking at a Fibonacci sequence.

See? I really wasn't kidding about patterns being all around us. Watch today's video and learn more about how to look at a sequence and see patterns. With three lectures, I'm betting you'll be seeing them everywhere. Just don't forget to click on the forward button directly to the left of the timestamp in order to see all the lectures. You won't want to miss a minute!

## 7th Grade Math - Permutations

Now that we've learned about combinations, it's time to take a look at a very similar concept called Permutations. Whereas a combination is a grouping of objects or events where order doesn't matter, a permutation is a grouping where order is very relevant. You might use a permutation to determine how many different ways there was to perform your chores in order. You could make your bed, take out the trash, and then feed the dog. Or maybe you want to feed the dog, take out the trash and then make your bed. Once you have determined all the possible ways of performing these tasks in order, you have figured out the permutation of your chores.

Watch Edward Burger demonstrate permutations over three different lectures in today's free 7th grade math video. Make sure you click on the forward button directly to the left of the time stamp in order to move to the next lecture as there are a total of three on the video. Then, try figuring out how you could use permutations in the real world! Maybe you need to create a combination for a bike lock. Did you know that four numbers can be ordered in a possible 10,000 ways if you allow for number repetition! That's a lot of possible lock combinations.

## 7th Grade Math - Combinations

A combination is a grouping of objects or events in which the order does not matter. Where might you see combinations in the real world? Well, a poker hand is a 5-combination of cards from a 52-card deck. Also, the lottery involves picking a random group of numbers where order does not matter. By calculating the combinations of each, it is possible to use a little math to determine the likelihood of your drawing a particular poker hand. You can even determine the probability of a particular number set being picked for the lottery. But that particular calculation would take quite a bit of math with all the possible numbers involved.

In today's free 7th grade math video, Professor Burger uses an example of a teacher wanting to pair up students in a classroom. Using a table, he shows all the different combinations that are possible. It can be a little tricky determining all the possible combinations, but after watching today's lectures, you should have no problem. Today's video has two lectures on it. To get to the second lecture, click the forward button directly to the left of the time stamp.

## 7th Grade Math - Making Predictions

Do you often wish you could predict the weather? Or maybe you'd like a leg up for picking your basketball brackets? Learning about making predictions can help you make better educated guesses. We're not saying you'll be the next Miss Cleo, but with a little bit of math you'll be able to make pretty good predictions.

Last week we posted a video on Experimental Probability. Today's free 7th grade math video is taking experimental probability and putting it to use in order to make predictions. Remember how we learned to compute experimental probability by taking the total number of times a particular event occurred and then dividing it by the total number of trials. In today's video, Edward Burger uses bowling as an example. In his first example he explains he has determined the experimental probability of making a strike is 20%. The prediction he wants to calculate is out of 400 rolls, how many would be strikes. Watch the video to learn exactly how to do this and you'll quickly be amazing your friends with your ability to make predictions. Today's video has a total of 3 lectures on it, so click on the forward button directly to the left of the time stamp when it's time to move to the next lecture.

I predict you will enjoy today's video and learn all you need to know about making predictions!

## 7th Grade Math - Theoretical Probability

So we know the difference between probability and experimental probability, but what about theoretical probability? Whereas experimental probability is the likelihood that a particular event happens, theoretical probability is the probability of an event when all outcomes are equally likely. In experimental probability, you determine the probability by dividing the number of times the event occurs by the total number of trials. With theoretical probability, you determine the probability by dividing the number of ways the event can occur by the total number of equally likely outcomes.

Confused? Don't be! Just check out today's free 7th grade math video and let Edward Burger teach you all about theoretical probability. In two lectures, he'll give you real world examples so that you have a strong understanding of the concept. Just don't forget to click on the forward button directly to the left of the timestamp to move to the next lecture on the video. And just in case that is not enough, we're publishing the subchapter worksheet for Introduction to Probability. Watch the videos and then test your knowledge with the worksheet. Between the two, you'll get a great overview in probability!

## 7th Grade Math - Experimental Probability

Experimental probability is a little different from regular probability. Instead, it is focused on looking at a particular circumstance and wanting to know the likelihood that a particular thing happens. To compute this experimental probability we look at all the instances where it did happen, count up all the instances total and take a ratio of successes over total number of equally likely outcomes. Whew! That's a mouth full!  Believe it or not, this is something you can easily experiment with at home. Roll a die and keep track of the numbers it displays each roll. Then choose a number and use experimental probability to determine how likely the die will land on that particular number.

Professor Edward Burger will help you fully understand this math concept as you progress through his two lectures on the subject. Using multiple real-world examples, you'll get a good foundation on how you could utilize experimental probability to find the likelihood that something will happen. Don't forget to click on the forward button to move to the next lecture.

If you like this video and would like to see more of what we have to offer, I highly recommend you check out our YouTube library.

## 7th Grade Math - Probability

Probability is a way of measuring how likely or unlikely an event will occur. Usually there are multiple possible outcomes of an event and it is possible to measure the probability of each. Probability is interesting because it is a mathematical concept used in a wide range of real world applications from statistics and finance to gambling, science and even philosophy. People are always interested in the likelihood of potential events occurring and probability allows us to express this mathematically.

In today's free 7th grade math video, Professor Edward Burger shows us the basics of probability. Not only does he demonstrate how to determine the probability of an event, he also shows us how to find the probability of an event not happening. Through several real world examples you'll gain a strong understanding of the concept of probability. Today's video has 3 lectures on it, so don't forget to click on the forward button directly to the left of the time stamp to move to the next lecture in the series.

## 7th Grade Math - Scatter Plots and Free Worksheet

A scatter plot, or scattergraph, is a type of chart that displays values for two variables for a set of data. Each axis on the graph represents a variable. In today's free 7th grade math video on Scatter Plots, Edward Burger uses two variables as an example: hours of study and math scores. By plotting each point from the number set, you'll find most likely find more meaning in the scatter plot than the table of numbers. As with most graphs, by visualizing the data, a trend may become clearer.

Professor Edward Burger will help you learn not only how to create a scatter plot, but also how to read one. Learn how to determine when there is no correlation between the two variables and when there is a negative or positive correlation. Today's video has 2 lectures on it, so make certain you click on the forward button directly to the left of the time stamp to move to the next lecture.

Since it's Friday, we're giving you a free worksheet as well! This covers the entire subchapter on Representing and Analyzing Data. Get a good idea of the types of worksheets that accompany our curriculum and maybe have a little fun with graphs and charts.

Have a great weekend!

## 7th Grade Math - Populations and Samples

Collecting data is much more than knocking on doors and polling people. To get accurate data that is a good representation of the public, you would ideally poll everyone in the population. Since it's nearly impossible to ask millions and millions of people questions, the best solution would be to poll a random sample group and then determine from them how everyone else might answer. In statistics, a sample is a subset of a population. It represents a subset of manageable size that one can use to make inferences from the sample to the population. Sampling is not perfect, but when utilized correctly, it can be a powerful tool to learn more about any population.

In today's free 7th grade math video, we cover Populations and Samples. Professor Edward Burger demonstrates different ways of sampling groups and how to determine if the sample is a good representation of the population or if it is a biased sampling. There are a total of three lectures on the video, so make certain you click on the forward button directly to the left of the timestamp to move to the next lecture in the series.

## 7th Grade Math - Line Graphs

Line graphs, or line charts, are great for taking tables of data and visualizing it. They make it easier to see patterns, structure and any surprising things that may come out of the data. You'll see line graphs utilized often in the real world as it is much more powerful to display data visually instead of publishing just the data set. In business, trends are often shared in some form of a line graph. You may have seen this represented on television whenever an executive is giving a presentation and pulls out a line graph to show a particular trend. This is because it is a much quicker way to make an impact with data when all a person needs to do is look at a chart.

In today's free 7th grade math video, Professor Burger demonstrates how to read line graphs, how to use a graph to estimate data, and how to create a double line graph to compare two data sets together. This lesson includes 3 lectures, so you'll need to click the forward button directly to the left of the timestamp to move to the next lecture.

Circle graphs, also known as pie charts, are a great way to display certain types of data. Since a circle graph is divided into sectors where each sector represents a proportion of the data set, we can get a sense of the data just by looking at it. Circle graphs are best used when trying to display data that are a percentage of the whole. That way we have the whole and can look at the different parts represented by sectors and easily see what part of the whole is represented by the percent.

You will most likely encounter circle graphs the most of all the charts due to the ease of reading them and their popularity.  In today's free 7th grade math video, Professor Edward Burger gives you several examples of circle graphs to give you a solid foundation in the subject. In the last of the three lectures, he shows how to decide what graph to use when displaying data. This is very important, as certain graphs will make it harder to read certain types of data.

So you can move through all three lectures on the video, don't forget to click on the forward button directly to the left of the time stamp to move to the next lecture!

## 7th Grade Math - Bar Graphs and Histograms

Bar graphs and histograms are wonderful ways of analyzing data in a very visual way where we gain quite a bit of information just by looking at the graph. It is often easier to see patterns in numbers when they are graphed, which is there are so many different types of graphs and charts.

You've most likely seen bar graphs in newspapers and anywhere else that are trying to convey data in a simple manner. However, histograms are a bit different. They are often known as distribution graphs as they allow you to see how a group of data is distributed. Each bar in a histogram represents the frequency of the observations during a particular interval. In the video, the example is number of students (frequency) and hours spent studying (interval).

In today's free 7th grade math video on Bar Graphs and Histograms, Edward Burger starts out by showing you how to read these charts and then teaches how to create them from a data set. You'll need to watch all 3 lectures on this video to get the entire lesson.  Make sure you click the forward button directly to the left of the time stamp to move to the next lecture!

## 7th Grade Math - Mean, Median, Mode, and Range

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This week we're going to focus on organizing and displaying data. Often, when looking at a lot of data, we want one number that somehow captures the essence of the whole. This is known as measuring the central tendency. In fact, there are several measures of central tendency. One is called the mean, or the average. It is when you add all of the numerical values and divide by the total number that you have. Then there is the median, which is the middle value when you order the values appropriately. There is the mode, which is the number that occurs the most. Finally, you have the range, the difference between the largest and smallest numbers.

In today's free 7th grade math video Edward Burger demonstrates the power of Mean, Median, Mode, and Range. You'll learn how to calculate all 4 measurements and work through a couple of examples to reinforce what you learned. The video has a total of 3 lectures, so make certain you click the forward button directly to the left of the time stamp to watch them all.

Also, don't forget to check out more of our videos on YouTube and our demo page. You'll get a good feel for our curriculum and the quality of our instructors.