Question

19. For each of the following claims

i) State the Null Hypothesis H0 and the Alternate Hypothesis HA

ii) Indicate which is the claim.

iii) Determine whether the reject region is left-tailed, right-tailed or two-tailed.

a) A consumer magazine reports that the mean life of a dot-matrix printer is at least 3.5 years.

b) A realtor claims that rent for studio apartments in new buildings in Brooklyn cannot be $1500 a month.

c) A car dealer announces that the mean time for an oil change in its service department is less than 20 minutes.

Answer 1

a)

The null and alternative hypothesis are

H0: >= 3.5 , Ha: < 35

Ha : < 35 is a claim.

This is left tailed test.

b)

The null and alternative hypothesis are

H0: = 1500 , Ha: 1500

Ha : 1500 is a claim.

This is two tailed test.

c)

The null and alternative hypothesis are

H0: >= 20 , Ha: < 20

Ha : < 20 is a claim.

This is left tailed test.