Q1: A pharmaceutical company claimed that 80% of enterotoxaemia in small ruminants are cured by its new drug Enterocare. 60 enterotoxaemia cases were treated with this drug. It was found that 42 of them were cured.

a) Calculate 95% confidence interval for the proportion of enterotoxaemia cured by that drug.

b) From part b, do you accept the claim of the company at a = 0.05? Explain why?

Q2: Consider the following set of numbers that represents a sample measurement from a normally distributed population:

59, 62, 59, 74, 70, 61, 62, 66, 62, 75

a) Compute a 95% t-confidence interval for . Use ta/2 = 2.262

b) Now suppose that you learn that . Compute a 95% z-confidence interval for . How does this compare to the interval in (a)?

Q3: A sample of mean X= 66 , and standard deviation S= 16, and size n= 11is used to estimate a population parameter. Assuming that the population is normally distributed, construct a 95% confidence interval estimate for the population mean, . Use ta/2 = 2.228.

Q4: Given the following hights of students in a college:

170 167 174 179 179 187 179 183 179 156 163

156 187 156 167 156 174 170 183 179 174 179

170 159 187.

Test the hypothesis that the average hight of students in that college is less than or equal 170with a = 0.05, Use = 1.71.

Q5: A sample of 30assistant professors has a mean salary of $43,260. At a= 0.05, test the claim that assistant professors earn more than $42000 . The standard deviation of the population is $5230

Q6: For Mean=29.84 ,a= 0.8andn= 100.

a) Find the 95% confidence interval.

a) Can we claim that u= 30? Explain why.