A cell phone company claims that the average time a person spends on their phone is 12.8 hours a week. A sample of unknown size of phone users was selected, and the mean time they spent on their phones was 12.2 hours in a week, with a standard deviation of 2.3 hours. Using a 90% confidence level, how many people would the company have to sample in order for their hypothesis to be true

30

Step-by-step explanation:

The sample size should be 30 for the given confidence interval of 90%.

Sample size is calculated as follows:

Sample size = Z score ^2 * standard deviation * [ 1 - Standard deviation] / margin of error^2

For the given 90% confidence level, the sample size calculated as;

Sample size = 1.645^2 * 2.3 [1 - 2.3] / 0.01^2

sample size = 30.

answer: 40.95

step-by-step explanation:

3-4

step-by-step explanation:

the answer is 3-4 because both 45 and 60 has a multiple of 15.

45/3=15

60/4=15

therefore the odds against selecting a red is 4-3