Please do question 12

10) In a random sample of 28 families, the average weekly food expense was $95.60 with a standard deviation of $22.50. Assume the population has a normal distribution . Determine whether a normal distribution or a t-distribution should be used or whet or whether neither of these can be used to construct a confidence interval. 11) For a sample of 200 IQ scores the mean score is 105.8. The standard deviation, o, is o, is 15. Assume the scores are not normally distributed. Determine whether a normal distribution n or a t-distribution should be used or whether neither of these can be used to con construct a confidence interval. 12) BONUS: Find the critical value zo that corresponds to a 94% confidence leve E = upper boundary - x