Question

Listed below are the amounts of net worth​ (in millions of​ dollars) of the ten wealthiest celebrities in a country. Construct a 90​% confidence interval. What does the result tell us about the population of all​ celebrities? Do the data appear to be from a normally distributed population as​ required?

243

218

176

172

162

155

147

147 147

142

What is the confidence interval estimate of the population mean μ​?

$___million < μ < $___ million

Answer 1

243 218 176 172 162 155 147 147 147 142 Mean Standard deviation Sample 170.9 33.87051 10

Given Given mean Standard deviation sample size X S n = 170.9 = 33.8705 = 10 level of confidence Level of significance Degrees of freedom C a df =n-1 = 0.9 = 0.1 = 9 Critical value 1.83311292 1.833 (three decimal places needed) 90 % Confidence interval is =Xt n Lower limit =ž - t* =170.9-(1.833*33.8705/10) = 151.2671 Vn Upper limit =ž +t*s =170.9+(1.833*33.8705/10) = 190.5329

90% confidence interval is (151.2671, 190.5329) With out rounding the t value three decimal places the confidence interval is Lower limit 151.2659078 Upper limit 190.5340922