# Statistics 4

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The manufacturer of Porshe 918 Spyder car claims that their car can go from 0 mph to 60 mph speed in less than 2.5 seconds. To test this claim, a sample of 40 new cars of this type were driven and their average 0-60 mph time was 2.6 seconds with a standard deviation of 0.5 seconds. Based on this information, would you believe the manufacturer’s claim? Use a 5% level of significance. State any assumptions you make. Clearly state the null and alternate hypotheses.
• A new television series must prove that it has more than 25% of the viewing audience after its initial 13-week run in order to be judged successful. Assume that in a sample of 400 households, 112 were watching the series. At a 10% level of significance, can the series be judged successful based on this information? State any assumptions you make. Clearly state the null and alternate hypotheses.
• A bath soap manufacturing process is designed with the expectation that each batch prepared in the mixture department will produce a mean of 120 bars of soap per batch. A mean over or under this standard is undesirable. A sample of ten batches shows the following numbers of bars of soap:
108, 118, 120, 122, 119, 113, 124, 122, 120, 123
Use a 5% level of significance and test to see the null hypothesis H0: =120 should be rejected.
State any assumptions you make. Clearly state the alternate hypotheses.

• Statistics 4 - ,