Confidence Interval question. See question details:

Data Science Interview QuestionsCategory: Data ScienceConfidence Interval question. See question details:
MockInterview Staff asked 6 years ago

In a local teaching district a technology grant is available to teachers in order to install a cluster of four computers in their classrooms. From 6250 teachers in the district, 250 were randomly selected and asked if they felt that the computers were an essential teaching tool for their classroom. Of those selected, 142 teachers felt that the computers were an essential teaching tool.

  1. Calculate a 99% confidence interval for the proportion of teachers who felt that computers are an essential teaching tool
  2. How could the survey be changed to narrow the confidence interval but to maintain the 99% confidence interval?

(There is a different version when the sample is less than 30 and if that is the case then you will use t-table/t-statistic to calculate the confidence interval. You can watch a Khan Academy video on that here)

1 Answers
MockInterview Staff answered 6 years ago

Plase see Khan Academy’s video on confidence interval: https://www.khanacademy.org/math/statistics-probability/confidence-intervals-one-sample/estimating-population-proportion/v/confidence-interval-example
Answer for #1 is: 48.8% to 64.8%
Answer for #2 is to increase the sample size. 

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