Math 146 – Introductory Statistics – Fall 2014
Name: ___________________________
Due: Monday Oct 6, 2014
Please do all work (neatly !) on this sheet.
1. Make an educated guess as to the distribution of the following variables. Make a small histogram
and describe the shape (symmetric, skewed, uniform, etc). Explain your answers.
a) Height of American adult males
b) Annual income of US households
c) Age of full-time college students
d) GPA of college seniors
2. Given the following sample data set:
32, 27, 35, 40, 36
Find the standard deviation. Show the table and your calculations. Use proper notation.
3.
x
2
--- means to square all the x-values and then add all the squared values
so if the x values are: 2 , 3, 4
 x 
2
2
= 4 + 9 + 16 = 29
--- means add up all the x values (you get a single number) and then square that number
so if the x values are: 2 , 3, 4
Find
x
x
2
and
 x 
2
 x 
2
= (2 + 3 + 4 )2 = 92 = 81
for the following data points:
-3, 5, -1, 6, 4
4. Find the standard deviation of the sample from #2 above using the following formula:
s
x
2
 ( x ) 2 / n
n 1
(formula is on p. 312 of text)
Show your calculations.
Compare your answer to the value you calculated in #1. Which formula was easier?
5. Given the following sets of data:
SampleA : 247.2 234.1, 254.7, 238.9, 251.0
SampleB: 20.1, -216.4, 146.0, -25.0, 83.1, -126.8
SampleC: 310.1, 309.8, 311.4, 310.5, 311.2
Without doing any calculations, answer the following:
a) Which set has the largest mean?
b) the largest s?
c) the largest s2 ?
d) Give another data set which has a smaller mean than SampleC and a larger s than SampleC.