# Question: A random sample of individuals who led their own income

A random sample of individuals who led their own income taxes were asked how much time (hours) they spent preparing last year's federal income tax forms.

(a) Estimate the mean.

(b) Estimate the standard deviation.

(c) Do you think the observations would be distributed uniformly within each interval? Why would that matter?

(d) Why do you imagine that un- equal bin sizes (interval widths) were used?

(a) Estimate the mean.

(b) Estimate the standard deviation.

(c) Do you think the observations would be distributed uniformly within each interval? Why would that matter?

(d) Why do you imagine that un- equal bin sizes (interval widths) were used?

## Relevant Questions

This table shows the distribution of winning times in the Kentucky Derby (a horse race) over 80 years. Times are recorded to the nearest 1 / 5 second (e.g., 121.4). (a) From the grouped data, calculate the mean. Show your ...(a) Make an Excel scatter plot of X = airspeed (nautical miles per hour) and Y = cockpit noise level (decibels) for 61 aircraft fights. (b) Use Excel's =CORREL function to find the correlation coefficient. (c) What do the ...Suppose Samsung ships 21.7 percent of the liquid crystal displays (LCDs) in the world. Let S be the event that a randomly selected LCD was made by Samsung. Find (a) P(S), (b) P(S), (c) The odds in favor of event S, and (d) ...Which pairs of events are independent? a. P(A) = .60, P(B) = .40, P(A ∩ B) = .24. b. P(A) = .90, P(B) = .20, P(A ∩ B) = .18. c. P(A) = .50, P(B) = .70, P(A ∩ B) = .25. A survey of 158 introductory statistics students showed the following contingency table. Find each event probability. a. P(V) b. P(A) c. P(A ∩ V ) d. P(A ∪ V ) e. P(A | V ) f. P(V | A)Post your question