Search & Filtering
Suppose we would like to determine the typical amount spent per customer for dinner. A
sample of 49 customers was randomly selected and the average amount spent was $22.60.
Assume that the amount spent is normally distributed and the population SD is known to be
$2.50.
a. Construct a 95% confidence interval for μ, the average amount spent per customer for
dinner.
b. Using a 0.02 level of significance, would we conclude the typical amount spent per
customer is more than $20.00?
A machine operates without a breakdown in 90% of the times on a given day. What is the probability that in one week of 6 working days there are at most 3 breakdowns that occur?
Select one:
0.9841
0.0159
0.9987
0.0013
Clear my choice
In a standard deck of 52
playing cards, 13
cards are clubs, and 3
of the clubs are “face” cards (K, Q, J). What is the probability of drawing one card that is:
- A club or a face card? Is this event a union or an intersection?
- A club and a face card? Is this event a union or an intersection?
- Not a club and not a face card?
A)To find the level of measurement : nominal,ratio,interval and ordinal
1)Jason measures time on days, with 0 corresponding to his birth date. The day before his birth is -1, the day after his birth date is +1, and so on. Jason has converted dates of major historical events to his numbering systems. What is the level of measurement of these numbers?
2)Which is relatively better: A score of 85 on a chemistry test or a score of 45 on an physics test? Scores on the chemistry test have a mean of 90 and a standard deviation of 10. Scores on physics test have a mean of 55 and a standard deviation of 5
Biostatistics (stem-and-plot). Please help me to find actual data.
Stem(hundreds) | Leaves (tens and units)
50 | 12, 12, 12, 55
51 |
52 | 00, 00, 00, 00
53 | 27, 27,35
54 | 72
You are choosing between 2 different card games. In the first game, every time a face card is selected from the deck randomly, you win. In the second game, every time a heart is chosen, you win. Which game should you choose and why?
If a farmer waits one week to sell his corn, there is a 50% chance that they will earn an extra $10 000. However, there is also a 10% chance that they will lose $30 000. Should he sell now or wait a week? Use the results of at least 25 experimental trials to support your answer.
Which is shorter, a 95% z-interval for the mean or a 95% t-interval for the mean? Is one of these always shorter, or does the outcome depend on the sample?
A news report summarizes a poll of voters and then adds that the margin of error is plus or minus 4%. Explain what that means.
A sample of 150 calls to a customer helpline during one week found that callers were kept waiting on average for 16 minutes with s = 8.
(a) Find the margin of error for this result if we use a 95% confidence interval for the length of time all customers during this period are kept waiting.
(b) Interpret for management the margin of error.
(c) If we only need to be 90% confident, does the confidence interval become wider or narrower?
(d) Find the 90% confidence interval.
