Jim is correct because the ratios need to compare with the total amount of people surveyed. 55, 80, and 65 are numbers that don't fit in and don't tell the overall ratio. You can tell this by writing it as a fraction.
Ex: 35:100 = 35/100. This literally means 35 out of 100 people exercise in the morning.
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Answer:
28
Step-by-step explanation:
18+6+4=28
Answer:
11
Step-by-step explanation:
in the "score" section all you do is add all them up. And because there is a negative for ALL the numbers, all you do is add a negative after you add all the SCORES
For margin of error to be a maximum of 3:
3 = z*(SD / sqrt(n)), where z is the z-score, SD is the standard deviation and n is the sample size.
z = 1.96 for a 95% confidence interval, and we are given SD = 15.
3 = 1.96*15/sqrt(n)
sqrt(n) = 9.8
n = 96.04 ~ 96 commercials.