Question

A random sample of 50 male employees is taken at the end of a year and the mean

number of hours of absenteeism for the years is found to be 63 hours. A similar sample of
50 female employees has mean of 66 hours. Could these samples be drawn from a
population with the same mean and standard deviation 10 hours?​

Answer 1

Yes the samples can be drawn from a population with the same mean and standard deviation 10 hours

Explanation:

We are given;

Sample mean for male employees; x1¯ = 63

Sample mean for female employees; x2¯ = 66

Sample size = 50

Standard deviation; σ = 10

First,let's define the hypotheses of the question;

Null hypothesis; H0: μ1 = μ2

Alternative hypothesis; Ha: μ1 ≠ μ2

Now, let's find the test statistic from the formula;

z = (x1¯ - x2¯)/(σ√(2/n))

Thus;

z = (63 - 66)/(10√(2/50))

z = -3/2 = - 1.5

Now, we are not given the significance value but usually when it is not given, we can adopt α = 0.05.

Thus, from online p-value from z-score calculator using; z = -1.5; α = 0.05; two tailed test; we have;

p-value = 0.13364

The p-value is greater than the significance value and thus we will fial to reject the null hypothesis and conclude that these samples can be drawn from a population with the same mean and standard deviation