Can anyone tell me how to use TI-84 calculator to solve this problem???
A company has developed a new type of light bulb, and wants to estimate its mean lifetime. A simple random sample of 12 bulbs had a sample mean lifetime of 692 hours with a sample standard deviation of 30 hours. It is reasonable to believe that the population is approximately normal. Find the lower bound of the 95% confidence interval for the population mean lifetime of all bulbs manufactured by this new process.
Round to the nearest integer. Write only a number as your answer. Do not write any units.
692-1.96*30/sqrt(12))
To find the lower bound of the 95% confidence interval for the population mean lifetime, you can use the TI-84 calculator by following these steps:
Step 1: Enter the sample statistics into the calculator:
- Press the "STAT" button on the calculator.
- Press the right arrow key to highlight the "Edit" menu and press "Enter" to select it.
- Enter the sample data into the calculator's list editor. In this case, you can enter the sample mean (692) into the L1 column and the sample standard deviation (30) into the L2 column.
Step 2: Calculate the confidence interval:
- Press the "STAT" button again.
- Press the right arrow key to highlight the "TESTS" menu and press "Enter" to select it.
- Press the down arrow key to highlight "8:TInterval" and press "Enter" to select it.
- Enter the necessary information into the TInterval dialog box:
- For "Data", select "Stats."
- For "Stats", select "L1" (which represents the sample mean).
- For "Freq", leave it as "1."
- For "Level", enter "0.95" for the 95% confidence level.
- For "Sigma", select "L2" (which represents the sample standard deviation).
- For "C-Level", leave it as "0."
- For "Prop", leave it as "0."
Step 3: Get the lower bound of the confidence interval:
- After entering the required information in the TInterval dialog box, press "Calculate" or "Enter" to calculate the confidence interval.
- The calculator will display the confidence interval on the screen as (lower bound, upper bound), where the lower bound is the value you are looking for.
The final answer should be rounded to the nearest integer, so simply round down the lower bound of the confidence interval to the nearest whole number.