Table 5.15 presents the ages for a number of individuals.
- Calculate the following statistics for the variable Age:
Table 5.15. Table with variables Name and Age
- Standard deviation
- An insurance company wanted to understand the time to process an insurance claim. They timed a random sample of 47 claims and determined that it took on average 25 minutes per claim and the standard deviation was calculated to be 3. With a confidence level of 95%, what is the confidence interval?
- An electronics company wishes to understand, for all customers that purchased a computer, how many will buy a printer at the same time. To test this, the company interviews a random sample of 300 customers and it was determined that 138 bought a printer. With a confidence level of 99%, what is the confidence interval for the proportion of customers buying a printer at the same time as a computer?
- A phone company wishes to make a claim that the average connection time in the US is less than two seconds (i.e. the time after you dial a number before the call starts to ring). To test this, the company measures 50 randomly selected calls and the average time was 1.9 seconds with a standard deviation of 0.26. Using this information and a 95% confidence level:
- Specify the null and alternative hypothesis ...