statistics home work 2
Instructions
| Excel #2 | |
| General Instructions | |
| 1. Responses to each page should be contained within that page. | |
| 2. Responses should be placed in the cell with the orange background. | |
| 3. Any tables needed for calcuations or answering questions should be clearly identified/labeled. | |
| 4. Calculations and tables must use cell references and appropriate functions (i.e., #s shouldn't simply be typed w/o work or procedures evident) | |
| 5. Reminder: this is an individual (not group) project. | |
| 6. No external resources except for your book/notes and instructor may be utilized | |
Page 1
| The following represents the observed distribution for the daily demand of tablets sold at the AT&T store. | |
| a. Determine the probability of each number of tablets being sold (0, 1, 2...). | |
| b. What is the expected daily demand of tablets? | |
| c. What is the probability that the store will have demand for at least five tablets? | |
| d., e. Calculate the variance and standard deviation for the daily demand of tablets. | |
| Demand | Frequency |
| 0 | 7 |
| 1 | 3 |
| 2 | 5 |
| 3 | 7 |
| 4 | 12 |
| 5 | 8 |
| 6 | 5 |
| 7 | 11 |
| 8 | 7 |
| 9 | 7 |
| 10 | 8 |
| b. | |
| c. | |
| d. | |
| e. |
Page 2
| Marcos is a car salesman. | |||||||
| Based on Marcos's previous experience, 18% of his potential customers ultimately buy a car from him. | |||||||
| Currently Marcos has five customers he is trying to convince to purchase a car. | |||||||
| a. Create the appropriate probability distribution below for each of the possible number of cars being sold. | |||||||
| a. Probability Distribution | |||||||
| b. How many cars would Marcos expect to sell? | b. | ||||||
| c. What is the probability that none of Marcos's customers purchase a car from him? | c. | ||||||
| d. What is the probability that all five of Marcos's customers purchase a car? | d. | ||||||
| e. What is the probability that a majority of Marcos's cars buy a car? | e. | ||||||
| f., g. Calculate the variance and standard deviation. | f. | ||||||
| g. | |||||||
| Marcos is looking to help determine how long customers spend at the car lot. | |||||||
| Preliminary measures indicate a customer spends an average of 12 minutes, following an exponential distribution | |||||||
| a. What is the probability that a customer will spend 5 minutes or less on the car lot? | |||||||
| b. What is the probability that a customer will spend no more than 12 minutes? | |||||||
| c. What is the likelihood that a customer will spend more than 30 minutes at the lot? | |||||||
| m | |||||||
| a. | |||||||
| b. | |||||||
| c. |
Page 3
| A sample of 25 LEGO sets sold by the LEGO Store is listed below. The data follow a normal distribution. | |||
| Item | Price | a. What is the average price of the LEGO sets? | |
| 1 | $19.99 | b. Determine the standard deviation of these LEGO sets. | |
| 2 | $15.99 | ||
| 3 | $42.99 | Mean | |
| 4 | $24.99 | SD | |
| 5 | $9.99 | ||
| 6 | $49.99 | c. What percentage of LEGO sets has a price of $30 or less? | |
| 7 | $31.99 | ||
| 8 | $32.99 | x | |
| 9 | $16.99 | z-value | |
| 10 | $24.99 | Probability | |
| 11 | $41.99 | ||
| 12 | $29.99 | d. What percentage of LEGO sets are priced at $60 or more? | |
| 13 | $44.99 | ||
| 14 | $31.99 | x | |
| 15 | $89.99 | z-value | |
| 16 | $52.99 | Probability | |
| 17 | $39.99 | ||
| 18 | $29.99 | d. What percentage of LEGO sets cost between $30 and $60? | |
| 19 | $53.99 | ||
| 20 | $24.99 | Probability | |
| 21 | $39.99 | ||
| 22 | $34.99 | ||
| 23 | $19.99 | ||
| 24 | $79.99 | ||
| 25 | $5.99 |
Page 4
| Thomas is interested in the average cost of car repairs at the BMW dealership. A sample 30 was taken and the results can be seen below. | |||
| The population is believed to be normally distributed and the standard deviation of the population is estimated to be $60. | |||
| Customer | Repair Cost | a. Calculate the mean repair cost and standard deviation of the sample of customers. | |
| 1 | $608 | b. What is the margin of error if a = .05? | |
| 2 | $514 | c. Determine the interval estimates for this level of confidence. | |
| 3 | $529 | ||
| 4 | $575 | Mean | |
| 5 | $637 | s | |
| 6 | $460 | a | |
| 7 | $412 | Margin of Error | |
| 8 | $480 | Interval Estimates | |
| 9 | $619 | ||
| 10 | $599 | ||
| 11 | $447 | Thomas is also interested in knowing what percentage of customers return for repairs within 6 months, but has no previous information regarding this statistic. | |
| 12 | $397 | ||
| 13 | $611 | ||
| 14 | $512 | d. What sample size would be needed to obtain this information within ± .05 at the 85% confidence level? | |
| 15 | $372 | ||
| 16 | $462 | a | |
| 17 | $434 | z-value | |
| 18 | $424 | proportion | |
| 19 | $413 | Margin of Error | |
| 20 | $542 | Sample Size | |
| 21 | $536 | ||
| 22 | $382 | ||
| 23 | $466 | ||
| 24 | $629 | ||
| 25 | $621 | ||
| 26 | $400 | ||
| 27 | $540 | ||
| 28 | $371 | ||
| 29 | $477 | ||
| 30 | $534 |