Question

An experiment that deals with the mental relation between weapon and aggression was considered in the Assignment for Unit 8. One of the variables in the experiment was "aw", the time of reaction for an aggressive target word following a weapon prime. It turns out that the average value of this variable among the 15 females that participated in the experiment is 40.33151 and the average among the 17 males is 41.43632. The sample standard deviation for female is 3.840025 and for males it is 6.371546. The confidence interval, with confidence level of 90%, for the variance of variable "aw" among males is: (Assume a Normal distribution for the variable. Choose the interval closest to the answer)

Select one:

a. [27.59, 69.75]

b. [4.33, 10.95]

c. [24.70, 81.58]

d. [3.88, 12.80]

Answer 1

Given:

For Females:

n = 15, Mean = 40.33151, SD = 3.840025, Variance = 14.74579

For Males:

n = 17, Mean = 41.43632, SD = 6.371546, Variance = 40.5966

Confidence level (C) = 0.90, = 1-C = 1-0.90 = 0.10

Critical value:

90% Confidence interval for the variance of variable "aw" among male is:

ANSWER: C. [24.70, 81.58]