Question

A safety administration conducted crash tests of child booster seats for cars. Listed below are results from those​ tests, with the measurements given in hic​ (standard head injury condition​ units). The safety requirement is that the hic measurement should be less than 1000 hic. Use a 0.01 significance level to test the claim that the sample is from a population with a mean less than 1000 hic. Do the results suggest that all of the child booster seats meet the specified​ requirement? 689     652     1145     629     634     751 what's the test statistic? what's the P value.

Answer 1

null hypothesis: Ho:             μ		=	1000
Alternate Hypothesis: Ha:μ		<	1000
0.01 level with left tailed test and n-1= 5 df, critical t=			-3.36
Decision rule :                   reject Ho if test statistic t<3.365
	population mean μ=	1000
	sample mean         x=	750.00
	sample size             n=	6
	sample std deviation s=	198.72
	std error sx=s/√n=	81.1271
	test stat t='(x-μ)*√n/s=	-3.082 (please try -3.08 if 2 decimal required)
	p value                                 =	0.0137 (please try 0.014 if 2 decimal required)