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For each of the following, state the parameter of interest, choice of test, and

ID: 3208739 • Letter: F

Question

For each of the following, state the parameter of interest, choice of test, and null hypothesis (in words).

a) A halogen bulb is claimed on average to last a minimum of 25 hours longer than a similar incandescent bulb.

b) 55% of middle school students prefer book bag A to A’s closest competitor, book bag B.

c) On the last state math test, the average performance for a random sample of urban districts was just as high as the average performance for a random sample of suburban districts.

d) Circulated reports indicated that a random sample of average pre-test and post-test scores of third grade students indicated that there were significant gains in average reading level over the course of third grade.

Explanation / Answer

(a) parameter of interest=average life of halogen

choice of test= z-test (if n>=30) or t -test (if n<30)of difference of means

null hyphesis H0:average life of halogen=similar incandescent bulb.

(b)

parameter of interest=proportion of preference of bag A

choice of test= z-test)of difference of proportion

null hyphesis H0:proportion of A=proportion of B

(c)

parameter of interest=average performance of math test

choice of test= z-test (if n>=30) or t -test (if n<30)of difference of means

null hyphesis H0:average urban=suburban.

(d) parameter of interest=average reading level over the course of third grade.

choice of test= z-test (if n>=30) or t -test (if n<30)of difference of means

null hyphesis H0:pretest=post test