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Confidence Intervals and Significance Levels

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68. In a study, Germination and Emergence of Broccoli, conducted by the Department of Horticulture at Virginia Polytechnic Institute and State University, a researcher found that at 5°C, 10 seeds out of 20 germinated, while at 15°C, 15 out of 20 seeds germinated. Compute a 95% confidence interval for the difference between the proportion of germination at the two different temperatures and decide if there is a significant difference.

70. According to USA Today (March 17, 1997), women made up 33.7 of the editorial staff at local TV stations in 1990 and 36.2% in 1994. Assume 20 new employees were hired as editorial staff.

a) Estimate the number that would have been women in each year, respectively.
b) Compute a 95% confidence interval to see if these is evidence that the proportion of women hired as editorial staff in 1994 was higher than the proportion hired in 1990.