Business Statistics, Ch. 7: Sampling and Sampling Distributions
How does normal distributions in Week 2 compare with sampling distributions for this week (i.e. week 3).
Candidate Jones believes she will receive .55 of the total votes cast in her county. However, in an attempt to validate this figure, her pollster contacts a random sample of 600 registered voters in the county. The poll results show that 298 of the voters say they are committed to voting for her. If she actually has .55 of the total vote, what is the probability of getting a sample proportion this small or smaller? Do you think she actually has 55% of the vote? Why or why not?
Suppose a random sample of turkey prices is taken from across the nation in an effort to estimate the average turkey price per pound in the United States. Shown here is the Minitab output for such a sample. Examine the output. What is the point estimate? What is the value of the assumed population standard deviation? How large is the sample? What level of confidence is being used? What table value is associated with this level of confidence? What is the confidence interval? Often the portion of the confidence interval that is added and subtracted from the mean is referred to as the margin of error of the estimate. How much is the margin of error of the estimate in this problem? (Please refer to the eTextbook).
As noted in the eTextbook Ch 8 Thinking Critically About Statistics in Business Today: Canadian Grocery Shopping Statistics, students must read to answer the following questions:
Things to Ponder
• Suppose a Canadian chain of large supermarkets wants to specifically appeal to customers making quick trips. What are some steps that the supermarkets could take to appeal more to customers making quick trips?
• Since 23% of buyers in this survey buy items that are not on their lists, what are some things that a store can do to encourage even more buyers to purchase items not on their lists?
As noted in the eTextbook Ch 8 Thinking Critically About Statistics in Business Today: Coffee Consumption in the United States, students must read to answer the following questions:
• What might be some reasons why a lower percentage of young adults drink coffee than do older adults? Of those young adults who do drink coffee, consumption is higher than for other groups. Why might this be?
• Note that the figures reported here are from a Gallup poll of around 1,000 respondents based on a 95% confidence interval with a ±4 percentage error. This report includes both means and percentages. In what ways do the statistics in this report tie-in to the information presented in this chapter?
Source: Adapted from Lydia Saad, “Americans’ Coffee Consumption is Steady, Few Want to Cut Back”, WELL-BEING, July 29, 2015, www.gallup.com/…/americans-coffee-consumption-steady-few-cut-back.as
How can you provide point and confidence interval estimates in personal and professional settings