Statistics and Probability

Question

In a survey, 32 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $43 and standard deviation of $10. Find the margin of error at a 95% confidence level.

Answer 1

32 people = N, normal distribution, mean=43, s = 10

95% CI, z= 1.96= about 2

(x-43)/10/sqr32 = 2

20 = sqr32(x-3)

x = 3 + 20/sqr32 = 3 + 5/sqr2 = about 6.5355= $6.54

MOE = zs/sqrN = 20/sqr32 = 20/4sqr2 = 5/sqr2