Name: ______

Lab #2: Due Wednesday, October 6

Instructions: You are to complete this lab by yourself. There is a lab problem which you will use to answer the 3 problems that comprise the lab. I’ve tried to bold the areas where an answer is required to make it easier for you, because in addition to the problems there is a lot of information contained in these sheets. Write your answers right on the lab and attach an EXCEL spreadsheet print out & a print out from your calculator where connectivity is available.

Lab #2 Problem:A teacher wants to create a multiple choice test in which the

answers are truly a simple random sample of a, b, c, d, and e’s. The teacher wants to use 10 questions and will choose 10, 1-digit numbers from a sample of random numbers to create the answers. The answer will be “a” if the digit is a 0 or 1, “b” if the digit is 2 or 3, “c” if the digit is 4 or 5, “d “if the digit 6 or 7 and “e” if it is 8 or 9.

Problem 1: Using the Random Number Table on A10, make a key.

a)Starting in row _____ on A10, the following are the first 10 digits.

b)My answer key is therefore:

Problem 2: Make a key using your TI calculator to get 10 random digits from which to form a key

a)Write down the 10 random numbers generated by your calculator.

b)Write the key here.

Recall:Calculator Example:MATH  PRB  randInt

You will need to give the calculator the parameters for the random number

generation in the following manner:

low value (comma)

high value(comma)

sample size

↵ (this is a return symbol when you see it in a calculator example/exercise)

For our example we would want the following to show on our calculator:

randInt (0, 9, 10↵

This will generate a list of 10 one digit random numbers as an array. You

can either copy these numbers down on paper or store them in your

statistics register. To store them you would do the following:

STO  L1 (this is the 2nd function 1 key)

To view your statistics register, use the following key combination:

STAT  EDIT (the edit menu is the 1st one & it will already be

highlighted so just return)

Problem 3:Make a key using Excel to get 10 random digits from which to form a key. Let EXCEL do the work of creating the key too.

a)Print out your EXCEL spreadsheet that contains the random numbers and

the key. Attach it to this lab.

b)Write your random numbers here.

c)Write your answer key here.

Recall:EXCEL Example:In Excel we can even do better! Not only can we create a

set of random digits, but we can also code them to show

our answers for us!! Since it is that decoding bit that is the

most painful portion of this exercise, we will truly

appreciate this! 

Either using the menu, function bar or typing =randbetween (in the a1 box)

we will create a set of 10 random numbers in column 1 (boxes a1-a10).

Menu Pull Downs:

INSERTFUNCTIONRANDBETWEEN

In a1 will look like:=randbetween(

Fill in with:Low Value (our case will be 0)

High Value (our case will be 9)

Function Bar:

Either with the fx or the ▼ next to the ∑ key, search for the

randbetween function (it is a math function; they are listed

alphabetically)

See instructions on Menu Pull Downs from here

Type In:

Type in the a1 box=randbetween(0,9)↵

Replicate this 9 times! To replicate, copy and paste the function that you

just created. This can be done one with menus or with hot keys.

Menu Pull Downs:

With the a1 box highlighted (left-click on the a1 box)

EDIT COPY

Now, left-click and hold, highlighting a2-a10

EDIT PASTE

Hot Keys:

Left-Click on a1 box

Control C (with a Mac it is apple c)

Left-Click and hold highlighting a2-a10

Control V (with a Mac it is apple v)

Note: With my Mac version Microsoft Office 2004, I did not have the randbetween function and had to use the rand function in conjunction with the round function. It looked like the following: =round(rand()*(9-0)+0,0) This rounds the random number generated to a whole number. The random numbers generated are any real number between 0 and 9. The last zero following the comma tells the round function that you want zero significant digits, in other words, zero decimals.

Now, the really cool part with EXCEL! We are going to let EXCEL make the key for us!

Click on box b1. Using any of the techniques above, Menus, Function Bar

or Type In, we want the “IF” function (this is a logic function). I’ll show

only for the type in version:

=IF(A1=0,"a",IF(A1=1,"A",IF(A1=2,"b",IF(A1=3,"B",IF(A1=4,"c",IF(A1=5,"C",IF(A1=6,"d",IF(A1=7,"D"))))))))

This will return the specified letters for each of the following and if it is a 8 or 9 which are unspecified it will return a FALSE so you will know it is E.

Replicate 9 times by left-clicking b1 and control c and then left-click on b2 and hold while dragging through b10 and control v.

Now, column A has 10 random numbers and column B has the answer key!

Y. Butterworth (M10)Lab #2 – Random Numbers 1of3