Lesson video

Hi, I'm Mrs. Wheelhouse, and welcome to our series of lessons on how to use your Casio calculator.

In these lessons, we're looking at three of the Casio calculator models, so let's get started.

By then today's lesson, you'll be able to use the fx-CG50 to perform calculations with data.

On the screen, you can see some of the keywords we'll be using today.

Feel free to pause the video and take a moment to read through these definitions.

And here is some more.

Again, feel free to pause the video so you have a chance to read through them.

Our lesson is broken into two parts today.

We're gonna begin with numerical summaries of data.

The arithmetic mean for a set of numerical data is the sum of the values divided by the number of values.

Izzy says, "Does this mean I need to use the calculate mode to add all the numbers before dividing?" Jun says, "No, no.

There's an easier way to calculate the mean." The fx-CG50 allows you to produce statistical summary very quickly.

From the main menu, navigate to the Statistics option and then press execute.

Here's a table showing the number of diners at various tables in a restaurant.

This represents three tables, each with four diners, and this represents two tables, each with five diners.

Enter the data in the same order into the table on the screen.

press CALC, or F2.

You now need to define what each list represents.

Press SET, or F6.

For the 1 variable XList, it should say List 1, and the 1 variable frequency should say List 2.

You can use LIST, F1, to change this if needed.

Press EXIT and then select 1-VAR, 1 variable, and that's the F1 button, to produce the statistical summary.

You can scroll down to see more.

The mean is written as x with a horizontal bar over the top of it.

This frequency table shows the number of goals scored in each match by all the teams in a club over one football season.

What was the mean number of goals scored? Pause the video and work this out now.

Welcome back.

Well, when you put this into your calculator, you should get the following statistical summary displayed.

And we can see that the mean is 1.

65 goals, which rounds to 2.

What was the median number of goals scored? Pause the video and work this out now.

Welcome back.

Well, we can see that the median number of goals and we can see that by scrolling down the calculator, is 1.

Izzy says, "Well, hang on, but what if I have a grouped frequency table?" And Jun says, "Well, your calculator can still find an estimate for the mean." 57 people were surveyed and asked how much money they spent on food during their visit to Oakfield Supermarket.

To calculate an estimate for the mean, we need to use the midpoint for each class.

Now, the calculator can do this for you.

We just need to type in the calculation to find the midpoint.

In other words, the lower bound of the class plus the upper bound of the class, so 0 and 20 in this case, sum them and divide by 2.

Don't forget those brackets.

Otherwise, your calculator won't know the order to do the operations in.

It will do division before addition.

When you've entered the calculation, press execute, and the calculator will evaluate what you've asked it to and produce the answer.

The midpoint is now displayed in the first column.

It's your turn now to calculate an estimate for the mean amount spent per visitor.

Pause the video and do this now.

Welcome back.

This is what you'll get if you input the correct midpoint and frequencies.

We can see that 68 pounds and 25 pence is the estimated mean amount spent per visitor.

Now, let's calculate an estimate for the median amount spent per visitor.

Pause the video while you write down your answer now.

Welcome back.

You can see that 35 pounds is the estimated median amount spent per visitor.

In other words, it falls in the 20 to 50 pound class.

It's now time for our first task.

This frequency table shows the star rating received by a restaurant over its opening weekend.

Part a, what was the mean star rating? And part b, what was the median star rating? Pause the video and work this out now.

Question 2.

The frequency table shows the number of bedrooms in different houses within an area of a town.

Part a, what is the mean number of bedrooms? And part b, what is the median number of bedrooms? Pause the video and work this out now.

Question 3, the time it takes for a sample of pupils to travel to school is collected in this grouped frequency table.

Part a, what does the estimated mean travel time to the nearest minute? And part b, what is the estimated median travel time to the nearest minute? Pause the video and work this out now.

It's now time to go through our answers.

For question 1 part a, what was the mean star rating? Well, it was 3.

64, et cetera, et cetera stars, which we know rounds to 4.

And what was the median star rating? It was 4 stars.

Question 2, what is the mean number of bedrooms? Well, it's 2.

5, which rounds to 3, and the median number is 2.

For question 3, the estimated mean travel time to the nearest minute is 18 minutes, and the estimated median travel time is 13 minutes.

Well done if you've got those right.

It's now time for the second part of our lesson and we're looking at graphical representations of data.

The fx-CG50 can plot scatter graphs and draw a line of best fit.

"Wow," says Izzy, "that's amazing!" Jun points out, "It can also perform calculations needed for A Level maths." So, it's a really powerful calculator.

The data below shows the age and heights for a sample of six children.

What do you notice about this data? While you can plot this scatter graph on your calculator using the statistics mode, let's begin by entering the data into the table.

Press GRAPH, or F1.

Pressing SET, F6, lets you determine which variable is on which axis and what the points will look like.

That's referred to as the Mark Type.

And you can see that here.

So, I've set the Mark Type to be a cross, because that's how I prefer my scatter graphs to look.

Press EXIT and then select GRAPH, or F1, and you can see the graph here that it generates.

Press CALC, F1, and then X, F2, and then the ax+b, F1 option.

On the next screen, press DRAW, F6, to see the line of best fit.

And here it is.

There appears to be a positive correlation.

The older child is, the taller they are.

It's now time for a quick check.

The data below shows the volume of water in a container over a period of time.

For part a, which variable should be plotted on the x-axis? Pause the video, have a think about this, and write down your thoughts now.

It should be the independent variable, which, in this case, is time.

Part b, sketch the scatter graph and line of best fit.

Your calculator can definitely help you here.

What do you notice about the data? Pause the video and work on this now.

Welcome back.

Well, when we sketch the scatter graph, it'll look like this, and we notice there is a positive correlation.

As time increases, so does the water volume.

It's now time for our final task.

For question 1, the table shows where the data from Bradford for five months in 2021.

What does this data suggest about the weather? Don't forget to justify your answer.

Pause the video and have a go at this now.

Question 2, Jacob runs a series of long-distance races.

For each race, he records his time and the elevation of the course.

What does this data suggest about elevation and the time taken? Don't forget to justify your answer.

Pause the video while you work on this now.

Welcome back.

It's time to go through our answers.

Well, when I use my calculator to plot this data, I saw that there appears to be a negative correlation.

In other words, the more it rains, the less sunshine we have.

For question 2, I noticed what appears to be a positive correlation.

In other words, the greater the elevation, the more time it takes to run the course.

Well done if you said something similar.

It's time to sum up what we've looked at today.

Some calculators can perform more than just basic calculations.

The fx-CG50 can produce a statistical summary of a set of data.

The summary includes the mean, median, upper and lower quartiles.

The fx-CG50 can produce graphical representations of data.

Well done, you've worked really well today.

I hope you've enjoyed exploring some of the features of the fx-CG50.

I look forward to seeing you for more math in the future.

Goodbye for now.