The average single smart phone cell phone bill is now averaging $73 with a standard deviation of $20. What is the probability that a sample mean of 40 produces a sample mean between $70 and $80?
The average single smart phone cell phone bill is now averaging $73 with a standard deviation...
The average single smart phone cell phone bill is now averaging $73 with a standard deviation of $20. What is the probability that a sample mean of 40 produces a sample mean equal to $73?
According to a report, the standard deviation of monthly cell phone bills was $49.64 three years ago. A researcher suspects that the standard deviation of monthly cell phone bills is different from today. (a) Determine the null and alternative hypotheses. (b) Explain what it would mean to make a Type I error. (c) Explain what it would mean to make a Type Il error. (a) State the hypotheses. Ho HY (Type integers or decimals. Do not round.) (b) Explain what...
9.14 The average credit card debt is currently averaging $15,000 (15) with a standard deviation of 5,000 (5). What is the probability that (use single digits): a. Mrs. Yono will have a debt of more than 9 thousand dollars? b.Mr. Lopez will have a debt more than 8 thousand? c. A sample of 20 people will have a debt less than 12 thousand? d. A sample of 20 people will have a debt between 14 and 16 thousand? 9.14 The...
The average monthly cell phone bill was reported to be $73.00 by the U.S. Wireless Industry. A random sampling of ten large cell phone company found the following monthly cell phone charges yields a sample mean of $78.47 with a population standard deviation of $7.41. At the 0.05 level of significance, can it be concluded that the average monthly cell phone bill differs from $73.00? Question 24 (2.63 points) Which test are you running? One mean z-test Chi-Square Goodness of...
A wireless company claims that the average of the customers cell phone bill is less than $90.00 per month. A sample of 75 customers reported that their average monthly bill is $84.25 with a standard deviation of $16.03. Test the claim at alpha=0.005
According to a report the standard deviation of monticell phone is was 545 three years ago. A researcher suspects that the standard deviation of monthly cell phone bills is higher today (a) Determine the two and a native hypotheses Explain what I would mean to make a Type I (c) Explain what it would mean to make a Type llo (a) State the hypotheses He Hi (Type Images or decias Do not round) b) Explain what it would mean to...
According to one study, the average monthly cell phone bill in the U.S. is $70. If a 20-year old student with an average bill gives up her cell phone and each month invests the $70 she would have spent on her phone bill in a savings plan that averages a 4% annual return, how much will she have saved by the time she is 65?
The amount of Jen's monthly phone bill is normally distributed with a mean of $50 and a standard deviation of $12. What percentage of her phone bills are between $14 and $86?
Your new cell phone has a mean lifetime of 5 years with a standard deviation of 1.5 year. What is the probability your cell phone will outlast your two year contract? Assume lifetime data is normally distributed.
Cell Phone Lifetimes A recent study of the lifetimes of cell phones found the average is 24.3 months. The standard deviation is 2.6 months. If a company provides its 32 employees with a cell phone, find the probability that the mean lifetime of these phones will be less than 23.7 months. Assume cell phone life is a normally distributed variable, the sample is taken from a large population and the correction factor can be ignored. Round the final answer to...