Question: The quality-control manager at a memory card manufacturing company needs to determine whether the mean data-transfer rate of a large shipment of cards is equal to 10 MB/s. The population standard deviation is 0.8 MB/s. A random sample of 64 cards indicates a sample mean data-transfer rate of 9.8 MB/s.

Required:

a) At the 0.05 level of significance, is there evidence that the mean data transfer rate is different from 10 MB/s?

b) Calculate the P-value and interpret its meaning.

c) Construct a 95% confidence interval estimate of the population mean data-transfer rate of the memory cards.

d) Compare the results of a) and c). What conclusions do you reach?