Using Your Casio 300W Calculator - Single-Variable Statistics

With very little effort you can learn to use your calculator to calculate a number of important single-variable statistics.

Objectives

By the end of this learning activity, you will be able to:

• Enter a data set into your calculator.
• Use your calculator to calculate the mean, standard deviation, and variance of a set of data.

The statistical functions of your calculator can save you from doing days and days of monotonous, repetitious busy work.

Modes:

Press the [ON] button.

Press [MODE] once and you should see:

You calculator is always in one of these modes (Comp, SD, or Reg).

• "Comp" is the computational mode and is used for general calculations such as addition, subtraction, division, and multiplication. To select "Comp" from the first menu, you press 1.
• "SD" is the standard deviation mode and is used for single-variable statistics to calculate the mean, standard deviation, and variance. To select "SD" from the first menu, you press 2.
Press [ON]
Press [MODE]
Press [2]
You should see a very small SD near the middle bottom of the screen. If you are my age, get out the bi-focals.
• "REG" is the regression mode and is used for two-variable statistics to calculate the mean, standard deviation, and variance. To select "REG" from the first menu, you press 3. We will not use the "REG" mode until module 3 but then you will be soooo happy to have this mode.
Press [ON]
Press [MODE]
Press [3]
Press [1] (we will only do linear regressions, never log or exponential (but it is nice to know we could if we wanted)
You should see a very small REG near the middle bottom of the screen - just above the [REPLAY] buttons.

Since we are gathered here today, my brothers and sisters, to learn about the single variable statistical functions, please put your calculator in SD mode.

To select "SD" from the first menu, you press 2.
Press [ON]
Press [MODE]
Press [2]
You should see a very small SD near the middle bottom of the screen.

Entering Data (Part 1):

This section assumes your calculator is in SD mode. Before we begin, I want you to locate the data entry key [M+] on your calculator. It is the button just above the read [AC] button. It is also important that you do not confuse the negative button [(-)] on the left side of your calculator with the subtraction button which is on the lower right side of your calculator. The negative button [(-)], just above the [STO] button, is used to enter negative numbers. The subtraction button [], just above the [=] button, is not used for data entry.

Let's imagine you want to find the mean, standard deviation, and variance of the following data:

 12 23 -5 14 4

Before you enter new data into your calculator, it is important that you clear the statistical memories.

Press [SHIFT] [AC] [=]

Your screen will show SCL for "Statistical Clear." Don't worry, this will disappear when we start entering data. Let's enter that data now:

Press [SHIFT] [AC] [=]

[1] [2] [M+]

[2] [3] [M+]

[(-)] [5] [M+] it is important that you press the negative button, not the subtraction button.

[1] [4] [M+]

[4] [M+]

That's it!! Wasn't that easy? We only need to enter the data once, and as long as we do not clear our calculator, we can ask our calculator to compute a number of different statistics (or parameters) based on that data.

Calculating the Mean, Standard Deviation, and Variance:

To obtain the mean press:

Before calculating the standard deviation and variance, you need to determine if your data constitutes the entire population or just a sample of a population.

If you have the data for the entire population:

To obtain the standard deviation, press [SHIFT] [2] [=]. Your display should read 9.478396489.

Once you have the standard deviation press [X2] [=] to get the variance. Your display should read 89.84.

If you have the data for only a sample:

To obtain the standard deviation, press [SHIFT] [3] [=] Your display should read 10.59716943.

Once you have the standard deviation press [X2] [=] to get the variance. Your display should read 112.3.

If your display did not show the numbers above, you probably pushed the red [AC] button when you should not have. When you press the red [AC] button, you clear out your data and need to re-enter all the data again before computing another answer based on that data. Moral to the story: Do not press the clear button unless you are entering a new data set.

Practice Opportunity:

1. What is the mean and variance of the following population.

24
74
21
-25
13
-35

Entering Data (Part 2) - Frequency Data

 Value Frequency 2 23 1 37 0 46 -1 102 -2 0 -3 1

The general form for entering frequency data is to enter the value then [SHIFT] [,] then the frequency then [M+]. The frequency is always positive. A value not followed by [SHIFT] [,] is treated as if the frequency is 1.

Before entering the data, make sure your calculator is in SD mode. Clear your statistical memories by pressing [SHIFT] [AC] [=].

Press [2] [SHIFT] [,] [2] [3] [M+]

 Before pressing the [M+] your display will say 2;23, (the [SHIFT] [,] becomes a semicolon. When you press the [M+] your display will say 2 (the value).

 [1] [SHIFT] [,] [3] [7] [M+] [0] [SHIFT] [,] [4] [6] [M+] [(-)] [1] [SHIFT] [,] [1] [0] [2] [M+] [(-)] [2] [SHIFT] [,] [0] [M+] [(-)] [3] [SHIFT] [,] [1] [M+] Value ; Frequency Enter

Practice Opportunity:

2. What is the variance and mean of the population from which the following data was sampled:

 Value Frequency 27 102 13 1 0 7 -12 13 24 0 -39 6