Question

The manager of Hybrid Motors wishes to determine if the true mean productivity of employees at its Detroit plant is more than that at its Mexico City plant (by measuring the number of cars that one employee is involved in the assembly of, per day).

Random samples of employees in Detroit and Mexico City are selected, and the productivity scores at each assembly plant are recorde .
The following results are obtained using a 30.01 and the MS Excel Detroit Mexico t-Test:
Two-Sample Assuming Equal Variances 67.3 56.5 59.2 61.3
Detroit Mexico 63 55.1 55.129 62.575
Mean 33.428 19.352 60.7 49.8
Variance 52.8 49
Observations 61.1 58.2 Pooled Variance 72.4 56
Hypothesized Mean Difference 0.000 64.1 13.000 t Stat P(T< t) one-tail t
Critical one-tail 2.650 P(T< two-ta t Critical two-tail 3.012 5.

The calculated value of the test statistic is:

A. 2.65

B. 3.012

C. 2.772

D. 0.008

E.0.016

Answer 1

A. 2.65

Explanation:

Let mu1 be the mean number of cars that one employee is involved in Detroit plant per day

And mu2 be the mean number of cars that one employee is involved in Mexico City plant per day

Null and alternative hypotheses are:

• 
  `H_(0)`: mu1-mu2=0

• 
  `H_(a)`: mu1-mu2>0

This is one tailed t test and one tailed test statistic is given as 2.650.