Exam 1 - HW 4

Determine whether the following statement is true or false. If the cashier used only data that were collected in a time frame preceding a big incoming snowstorm, the average number of gallons of milk sold per customer calculated from the sample would likely be inflated due to nonresponse bias.

False

Determine whether the following statement is true or false. This method of questioning would likely cause the sample statistic to overestimate the true population parameter.

False

Determine whether the following statements are true or false. A pollster goes door-to-door during the day to determine what percentage of households watch soap operas. The pollster would be able to obtain responses only from those who are home during the day. This is an example of nonresponse bias.

False

A cashier at a local grocery store wanted to estimate the mean number of gallons of milk customers were purchasing. She received sales data on the number of gallons of milk sold per customer from the manager's office. The data set contained milk sales data per customer for over 1,000 customers. She randomly selected 10 shoppers. The number of gallons of milk purchased were as follows. 1, 1, 6, 1, 1, 4, 1, 1, 2, and 2 The average number of gallons purchased by these 10 customers is 2 gallons per customer. (a) This technique will introduce what type of bias? nonresponse bias response bias selection bias no bias is being introduced

no bias is being introduced

A farmer would like to know if a new brand of fertilizer produces more tomatoes than the current brand of fertilizer. He takes a random sample of 50 tomato plants from his crop and specifically treats them with the new fertilizer. All other plants receive the current fertilizer. The method utilized by the farmer likely introduces which of the following sources of bias? nonresponse bias response bias selection bias no bias is being introduced

no bias is being introduced

What type of bias occurs when responses are not obtained from all individuals selected for the sample? nonresponse bias response bias selection bias no bias is being introduced

nonresponse bias

When a study contains sources of bias, the sample result may ______________ the true population parameter.

overestimate or underestimate

An advisor calls students to her office, one at a time, to ask them face-to-face how many times they have skipped class this semester. What type of bias is introduced by this type of questioning? nonresponse bias response bias selection bias no bias is being introduced

response bias