Question

A study is being conducted to compare the average training time for two groups of airport security personnel: those who work for the federal government and those employed by private security companies. From a random sample of 12 government-employed security personnel, average training time was 72 hours, with a sample standard deviation of 8 hours. In a random sample of 16 privately employed security personnel, training time was 65.4 hours, with a sample standard deviation of 12.3 hours. Assume that training time for each group is normally distributed. Use the following notations:

μ1: The mean training time for the population of airport security personnel
employed by the federal government.
μ2: The mean training time for the population of airport security personnel
employed by private security companies.
The goal of the statistical analysis is to determine whether the sample data support the hypothesis that average training time for government-employed security personnel is higher than those employed by private security companies.
1. What is the null hypothesis H0?
Select one:
a. μ1- μ2 <= 0
b. μ1- μ2 < 0
c. μ1- μ2 =/ 0
d. μ1- μ2 > 0
2. What is the alternative hypothesis Ha?
Select one:
a. μ1- μ2 > 0
b. μ1- μ2 <= 0
c. μ1- μ2 = 0
d. μ1- μ2 >= 0

Answer 1

1.a. H₀: μ₁ - μ₂ ≤ 0

2.b. H₁: μ₁ - μ₂ > 0

Explanation:

Hello!

The objective is to compare the average training time for two groups of airport security personnel.

Group 1: Security personnel that works for the federal government

n= 12

X[bar]= 72 hs

S= 8hs

Group 2: Security personnel from private companies

n= 16

X[bar]= 65.4 hs

S= 12.3 hs

The goal of the analysis is to test if the average training time for government-employed security personnel is higher than those employed by private security companies, symbolically: μ₁ > μ₂

The null and alternative hypotheses are complementary and exhaustive.

The null hypothesis always represents the "no change situation" and therefore always carries the = symbol. Generally, the researcher's claim is stated in the alternative hypothesis.

With all this in consideration, the hypotheses for this experiment are:

H₀: μ₁ ≤ μ₂

H₁: μ₁ > μ₂

I hope this helps!