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(1.5 points) If the standard deviation of hole diameter exceeds 0.01 millimeters

ID: 2955623 • Letter: #

Question

(1.5 points) If the standard deviation of hole diameter exceeds 0.01 millimeters, there is an unacceptably high probability that the rivet will not fit. Suppose that n = 15 and s = 0.008 millimeters.
a. Is there strong evidence to indicate that the standard deviation of hole diameter exceeds 0.01 millimeters? Use a = 0.01. State your conclusions explicitly. What does rejecting or not rejecting null hypothesis mean?
b. Find the P-value for this test.
c. Suppose that the actual standard deviation of hole diameter exceeds the hypothesized value by 50%. What is the beta in part (a)? Show ?.
d. If s is really as large as 0.0125 millimeters, what sample size will be required to defect this with power of at least 0.8? Show ?.

Explanation / Answer

given that                  n=15,s=0.008 a) Ho=s=0.01 H1=s>0.01    by using chisquare test =(n-1)(s^2)/(s^2)                        = 14(0.008*0.008)/0.0001                          =8.96          the tabulated value of  chi square deg. of freedom at 14 is 6.57                    here   calucated chisquare> tabulted chisquare therefore we reject the null hypothsis          b) the p value is                          p(chisquare<tab of chisquare)         therefore we reject the null hypothsis          b) the p value is                          p(chisquare<tab of chisquare)