Question

The means of the number of revolutions per minute of two competing types of engines are to be compared. Thirty engines are randomly assigned to be tested for each type. Both populations have normal distributions. The table below shows the result. Do the data indicate that Engine 2 has higher RPM than Engine 1? Test at a 5% level of significance. Type of engine X 1 1,500 50 1,600 60 0 2

Answer 1

To determine if Engine 2 has a higher mean RPM than Engine 1, we need to perform a hypothesis test. Let's denote:

μ1: the true mean RPM of Engine 1
μ2: the true mean RPM of Engine 2
The null hypothesis (H0) states that there is no significant difference between the means of the two engines:

H0: μ1 - μ2 = 0

The alternative hypothesis (Ha) states that Engine 2 has a higher mean RPM than Engine 1:

Ha: μ1 - μ2