1. Unit 0, Session 0.4 Useful Calculator Functions
J. Jackson Barnette, PhD
Professor of Biostatistics

2. Calculator for Course
You probably don’t need to buy a calculator for this course; you are probably carrying the best (and cheapest) calculator you can get as: There are hundreds of apps, mostly free, that will do everything you need to do in this class and more
Unit 0, Session 0.1
Copyright 2013 JJ Barnette

3. Session 0.4 Calculator Functions
0.4 Useful Calculator Functions
Introductory Biostatistics
Session 0.4 Calculator Functions
There are many types of calculators that can be used in this class
There are some that do many of the complex computations with a few keystrokes
I will illustrate some of these using one of my hand calculators, a CASIO fx-115MS
Keys vary by calculators so yours may be different, but should have the same operations that can be done
Unit 0, Session 0.4
Copyright 2013, JJBarnette

4. 0.4 Useful Calculator Functions
Introductory Biostatistics
SQUARE-ROOT
Finding a Square-root. The order of the key strokes is important and will vary.
To find the square-root of a given number, press the square-root key, then enter the number on the keypad, and press the equal sign.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

5. 0.4 Useful Calculator Functions
Introductory Biostatistics
SQUARE-ROOT
To find the square-root of a value that has been calculated using other operations, press the square-root key, then press the Answer key, and then press the equal sign. This will find the square-root of the previous answer.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

6. 0.4 Useful Calculator Functions
Introductory Biostatistics
FACTORIAL
To find a factorial X!, enter the number X, press the SHIFT key, then the factorial key, then the = sign key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

7. 0.4 Useful Calculator Functions
NATURAL LOG
To find the natural logarithm of a number, press the ln key, then enter the number, then the = sign key.
If you want the natural log of a computed answer, press ln, then Ans, then the = sign.
0.4 Useful Calculator Functions
Introductory Biostatistics
Unit 0, Session 0.4
Copyright 2013, JJBarnette

8. 0.4 Useful Calculator Functions
Introductory Biostatistics
MULTIPLYING BY e
To multiply a number
by the constant e
( ), press the
ALPHA key, then the
e key, then the
multiplication key (X),
enter the number to
be multiplied, and
then press the = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

9. 0.4 Useful Calculator Functions
Introductory Biostatistics
FINDING e TO A
POWER, ex
Used to convert a
natural log back to an original scaled value. Press the SHIFT key, press the ex key, enter x on the keypad (the exponent, include – sign if negative), then press = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

10. 0.4 Useful Calculator Functions
Introductory Biostatistics
TAKING A VALUE
TO A POWER, Xy
Many calculators
have this key. If so,
enter X, then press
the key, then enter y
(the exponent), then =.
On mine, enter X on
the keypad, press
the ^ key, then enter
y (the exponent), and
then press =.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

11. Combinations and Permutations
0.4 Useful Calculator Functions
Combinations and Permutations
Introductory Biostatistics
When we study the topic of probability, we will use two types of counting procedures
One is the number of combinations of r items taken from n different possible items (see 0.2, 8),
The other is the number of unique sequences of r items taken from n possible items. These are Permutations (see 0.2, 9),
These are very time-consuming to compute from scratch, many calculators do these automatically
Unit 0, Session 0.4
Copyright 2013, JJBarnette

12. Combination Key
Order: Enter n first, press key, enter r next, press = sign
Unit 0, Session 0.4

13. 0.4 Useful Calculator Functions
Introductory Biostatistics
COMBINATIONS, nCr
Combinations are the
number of unique
combinations of r
items taken from a
group of n different
items.
Here’s the key (SHIFT)
on my calculator
that finds this.
Enter n on the
keypad, press the
nCr key, enter r and
then the = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

14. 0.4 Useful Calculator Functions
Introductory Biostatistics
COMBINATIONS, nCr
Combinations are the
number of unique
combinations of r
items taken from a
group of n different
items.
Here’s the key (SHIFT)
on my calculator
that finds this.
Enter n on the
keypad, press the
nCr key, enter r and
then the = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

15. Permutation Key
Order: Enter n first, press key, enter r next, press = sign
Unit 0, Session 0.4

16. 0.4 Useful Calculator Functions
Introductory Biostatistics
PERMUTATION, nPr
Permutations are the
number of unique
sequences of r items
taken from a group
of n items.
Here’s the key (SHIFT)
on my calculator
that finds this.
Enter n on the
keypad, press the
nPr key, enter r and
then the = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

17. 0.4 Useful Calculator Functions
Introductory Biostatistics
PERMUTATION, nPr
Permutations are the
number of unique
sequences of r items
taken from a group
of n items.
Here’s the key (SHIFT)
on my calculator
that finds this.
Enter n on the
keypad, press the
nPr key, enter r and
then the = key.
Unit 0, Session 0.4
Copyright 2013, JJBarnette

18. Conclusion
This is the final session in Unit 0 It is intended as a review of basic mathematics used in biostatistics with a focus on how these will be used in this course If there are mistakes found of other topics that you feel should be included, please contact Dr. Barnette
Unit 0, Session 0.4