re Women Getting Taller? A researcher claims that the average height of a woman
ID: 3324080 • Letter: R
Question
re Women Getting Taller? A researcher claims that the average height of a woman aged 20 years or older is greater than the 1994 mean height of 63.7 inches, on the basis of data obtained from the Centers for Disease Con- trol and Prevention's, Advance Data Report, No. 347. She btains a simple random sample of 45 women and finds the sample mean height to be 63:9 inches. Assume that the population standard deviation is 3,5 inches., Test the re- searcher's claim using either the classical approach or the P-value approach at the = 0.05 level of significance.Explanation / Answer
SOLUTION:
Ho: mu=63.7
Ha:mu> 63.7
alpha=0.05
test statistic:
z=sample mean-pop mean/samplesd/sqrt(n)
=63.9-63.7/3.5/sqrt(45)
z =0.383
z cal=0.383
Decsion Rule:
if Z cal > Zcrit reject Null Hypothesis.
if Z cal<Z crit ,fail to reject Null hypothesis.
Decsion:
here Z cal=0.383
Z crit for 95%=1.96
Z cal<Zcrit
Fail to reject Null hypothesis.
Accept Null hypothesis.
there is no sufficient evidence at 5% level of significance to support the claim that average height is greater than 63.9 inches
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