Question

Question 21 --/1 View Policies Current Attempt in Progress Effect of Splitting the Bill A study compared the cost of restaurant meals when people pay individually versus splitting the bill as a group. In the experiment half of the people were told they they would each be responsible for individual meals costs and the other half were told the cost would be split equally among the six people at the table. The 24 people paying individually had a mean cost of 37.29 Israeli shekels with a standard deviation of 12.54, while the 24 people splitting the bill had a higher mean cost of 50.92 Israeli shekels with a standard deviation of 14.33. The raw data can be found in SplitBill and both distributions are reasonably bell-shaped. Use this information to find a 95% confidence interval for the difference in mean meal cost between these two situations. Click here for the dataset associated with this question. Round your answers to two decimal places. The 95% confidence interval is i e Textbook and Media Attempts: 0 of 3 used Save for Later Submit Answer

Answer 1

Solution: Given that 95% Confidence interval
x1 = 37.29, s1 = 12.54, n1 = 24
x2 = 50.92, s1 = 14.33, n1 = 24
df = n1+n2-2 = 48-2 = 46, t = 2.013

95% Confidence interval for the difference mean =
= (x1-x2) +/- t*sqrt(s1^2/n1)+(s2^2/n2))
= (37.29-50.92) +/- 2.013*sqrt((12.54^2/24)+(14.33^2/24))
= (-21.45 , -5.81) rounded