Question

how do Ifind the sample mean or sx for the problem below?         

Assume that a simple random sample has been selected from a normally distributed population and test the given claim. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.

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

0.05

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?

     

701

     

1186

     

555

     

505

     

440

Answer 1

The sample mean for standard head injury condition is obtained using the formula,

The sample standard deviation is obtained using the formula,

From the data values,

701	677.4	23.6	556.96
1186	677.4	508.6	258673.96
555	677.4	-122.4	14981.76
505	677.4	-172.4	29721.76
440	677.4	-237.4	56358.76
		Sum	360293.2