Question

Ten newborn gorillas are weighed, giving the following data, in lbs. : 35, 37.1, 41, 40.9, 39.5, 38, 29, 27, 30.1, 35.2.

a) construct the boxplot for this data

b) find the mean and standard deviation of the newborn gorilla weights

16. Typically political polls, where they show the percentage of Americans with certain preferences, have a margin of error of 3%, and a confidence level of 95%. What sample size is needed by ABC News if they want just a 1% margin of error and a 99% confidence level for their political polls?

Answer 1

Solution:

a)

b)

Mean = (35 + 37.1 + 41 + 40.9 + 39.5 + 38 + 29 + 27 + 30.1 + 35.2)/10
= 352.8/10
Mean = 35.28

Standard Deviation σ = √(1/10 - 1) x ((35 - 35.28)2 + (37.1 - 35.28)2 + (41 - 35.28)2 + (40.9 - 35.28)2 + (39.5 - 35.28)2 + (38 - 35.28)2 + (29 - 35.28)2 + (27 - 35.28)2 + (30.1 - 35.28)2 + (35.2 - 35.28)2)
= √(1/9) x ((-0.28)2 + (1.82)2 + (5.72)2 + (5.62)2 + (4.22)2 + (2.72)2 + (-6.28)2 + (-8.28)2 + (-5.18)2 + (-0.079999999999998)2)
= √(0.1111) x ((0.078400000000001) + (3.3124) + (32.7184) + (31.5844) + (17.8084) + (7.3984) + (39.4384) + (68.5584) + (26.8324) + (0.0063999999999997))
= √(0.1111) x (227.736)
= √(25.3014696)
= 5.0303