Question

Twenty-five randomly selected students were asked the number of movies they watched the previous week. The...

Twenty-five randomly selected students were asked the number of movies they watched the previous week. The results are as follows.

# of movies Frequency
0 5
1 10
2 6
3 3
4 1

(a) Find the sample mean x. (Enter your answer to two decimal places.)

x=

(b) Find the approximate sample standard deviation, s. (Round your answer to two decimal places.)

s =

Homework Answers

Answer #1

Solution,

no. of movies (x) frequency (f) f * x f * x2
0 5 0 0
1 10 10 10
2 6 12 24
3 3 9 27
4 1 4 16
Total 25 35 77

n = 25

a) Sample mean = x = f * x / n = 35 / 25 = 1.40

b) Sample standard deviation = s = ( f * x2 / n - 1 ) - ( n * x2  / n - 1 )

s = (77 / 24) - ( 25 * 1.402 / 24 )

s = 3.20 - 2.04

s = 1.16

s = 1.08

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