8) The health of the leopard population in a Safari Park is monitored by measurements. A sample of 86 leopards has a mean weight of 169.8 lb. Assume that the population standard deviation is known to be 46.5 lb. and find a 93% confidence interval estimate of the mean of the population and find the margin of error. 9) The music industry must adjust to the growing practice of consumers burning CDs by downloading from Internet instead of buying. How many randomly selected song purchases must be surveyed as a simple random sample, if 42% of songs in that sample were obtained by downloading from Internet? Assume that we want to be 95% confident that the sample percentage is within four percentage points of the true population percentage. 10) An average household in Ohio spends $197 per day. A sample of 60 households in Toledo, showed a sample mean daily expenditure of $189. Assume that the population standard deviation is $27.6. Test the claim that the average daily expenditure of the Ohio population differs from $197. Use a 91% confidence level. alpha=0.09 (significance level). a) Formulate the null and alternative hypotheses. b) What is the rejection rule and the p-value? Is the claim valid