Statistics


Question 1.

The following table gives the distribution of quiz scores on a quiz in a 30 person class. 
		score  |  10	9	8	7	6
		-------|------------------------------------
                number |   4	6	10	8	2
A. Draw a histogram to represent the distribution.

B. What is the probability a person scored below 8 on the quiz?

C. What is the mean quiz score?

D. What is the median quiz score?

Question 2.

A study of a brand of tires found the tire life (in thousands of miles) as follows:
			Number Miles   |  Number tires
			---------------|--------------
                             32        |     3
                             40        |     5
                             48        |     2
The average (Mean) number of miles of tire life is 39.2 (thousand).
A. Find the variance in the number of miles the tires lasted.

B. Find the standard deviation of tire life.

Question 3.

Which histogram below has the smaller standard deviation?
A. B.

Question 4.

The deer population in a county is normally distributed with mean 400 and standard deviation of 75. What is the probability that the deer population is

a. greater than 550?

b. less than 400?

c. between 325 and 550?

d. less than 475?


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