Answer:
A Null hypothesis (H0): mu equals 200 sec
Alternate hypothesis (H1): mu greater than 200 sec
Test statistic (z) is 5.31
Critical value is 1.645
Conclusion: reject the null hypothesis
Final conclusion that addresses the original claim: the result obtained suggest that the advice given in the manual is not valid
Step-by-step explanation:
Null hypothesis is a statement from the population parameter subject to testing
Alternate hypothesis is also a statement from the population parameter that negates the null hypothesis
Test statistic (z) = (sample mean - population mean) ÷ sd/√n
sample mean = 245 sec, popi mean = 200 sec, sd = 53.5 sec, n = 40
z = (245 - 200) ÷ 53.5/√40 = 45 ÷ 8.47 = 5.31
This is a one tailed test.The critical value using a significance level of 0.05 is 1.645
Conclusion: since the test statistic (5.31) is greater than the critical value (1.645), reject the null hypothesis
Final conclusion: There is sufficient evidence to support the claim that the sample is from a population of songs with a mean greater than 200 sec
This result suggest that the advice offered in the manual is not valid
