Question

An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 170 engines and the mean pressure was 4.7 Ibs/square inch. Assume the variance is known to be 1. If the valve was designed to produce a mean pressure of 4.5 lbs/square inch, is there sufficient evidence at the 0.05 level that the valve does not perform to the specifications? State the null and alternative hypotheses for the above scenario. E Tables E Keypad Answer Но Н Submit Answer

Answer 1

given, 'n=170, x=4.7,6² = 1 x=0.05 Null and Alternative hypothesis, Ho.l=4.5 Hall & 4.5 the test statistics is, 2 = 7-1 - 4.7-4.5 16% 1170 [2= 2.6 The p-value is, - PCIZI > Z) > Z) =P ( z<-2 ) + P(Z = 2xP(Z c-2) = 2xP (2<-2061) = 2X0.0045 = 0.009 P-vallee = 0.009 Here p-value <2=0.05 . Hence, we reject the null hypothesis. conclusion :- Reject the hell hypothesis (Ho). There is sufficient evidence at 0.05 leved that the value does not perform to the specification.