Note in 31 and 33 there are some tedious calculations that I did for you. You can see the output once you knit this file.

9.2

21.

  1. doesn’t discuss being 95% confident

  2. Right

  3. doesn’t discuss being 95% confident

  4. doesn’t talk about adult Americans.

23.

We are 90% confident that the mean drive time in Taco Bell is between 161.5 and 164.7 seconds

25.

You could 1) have a larger sample size or 2) have a smaller level of confidence to get a smaller confidence interval

27.

  1. A larger sample population is needed because the distribution will be closer to one.

  2. 51 is less than 5% of the population size

  3. lower fence is .1647 and upper fence is .1693

  4. It would be possible because there’s a margin of error, but highly unlikely.

29.

lower fence: 318.16 upperfence: 394.04

31.

  1. mean = 4.8925

  2. lower fence = 4.7101 upper fence = 5.0699

data <- c(4.58,5.72,5.19,4.75,5.05,5.02,4.8,4.74,4.77,4.76,4.77,4.56)
mean(data)
## [1] 4.8925
sd(data)
## [1] 0.3194064
  1. lower fence: 4.6537 upper fence: 5.1263

d)the interval increases and the margin of error increases

33.

  1. skip

  2. skip

data2 <- c(3148,2057,1758,663,1071,2637,3345,773,743,1370)
mean(data2)
## [1] 1756.5
sd(data2)
## [1] 1007.454

  1. lower fence: 1132.31 upper fence: 2, 380.69

  2. narrower because there is less variability

9.3

5.

between 10.117 and 30.114

7.

between 9.542 and 40.289

9.

  1. lower: 7.949 upper: 23.66

  2. lower: 8.586 upper: 20.634

  3. lower: 6.614 upper: 31.36

11.

lower: .226 upper: .542

13. lower: 734.8 upper: 1657.5