Books? Books? Books? Calculators out and ready to review!

Final Review Day 2

Create a Quiz! Sample vs. Population Response/Explanatory Variable Positive/Negative Correlation Weak vs. Strong Correlation Coefficient ŷ = a + bx (positive vs. negative slope)

Explanatory/Response Suppose you were to collect data for a pair of given variables in order to make a scatterplot. For the variables cloudy days and rainy days, which is more naturally the response variable and which the explanatory variable? Ex: Cloudy, R: Rainy

Explanatory/Response Suppose you were to collect data for a pair of given variables in order to make a scatterplot. For the variables time spent on homework and exam grades, which is more naturally the response variable and which the explanatory variable? Ex: Time on HW, R: Grades

Proportions The partially completed conditional proportion table gives the relative frequencies of the data on age (in years) and gender for the residents of a retirement home. What percentage of the residents are males over 79?

Proportions The partially completed conditional proportion table gives the relative frequencies of the data on age (in years) and sex for the residents of a retirement home. What percentage of the residents are females in the age group 70 - 79?

Complete the Table 25 15 20 11 9 40

Correlation – positive, negative

Correlation – positive, negative NONE

Correlation – positive, negative

Correlation – strongest?

True or False? The closer r is to 0, the weaker the linear association between the variables.

The value of the correlation is always between 0 and 1. True or False? The value of the  correlation  is always  between 0 and 1.

Find the equation of the line of best fit in your calculator x 2 4 5 7 8 y 12 15 17 22 25

Association implies causation. True or False? Association implies causation. Remember, eating ice cream didn’t CAUSE drownings…they just happened to occur at the same time of year (correlated).

A survey of adults revealed a positive correlation between the height of the subject and their income in the previous year. Explain how gender could be a potential lurking variable that could be responsible for the association.

How many males were asked? Opinion About Life After Death by Gender Opinion about life after death Gender Yes No Male 417 125 Female 541 88 542

Positive or Negative Slope? ŷ = -209.9 + 25.5x Positive! (# in front of x)

What is the percent of variation? If r is 0.67… Is this strong or weak? What is the percent of variation? 44.89%

If y = 50.15 when x = 45.1, what is the residual? ^ y – y

A drug company needs to test a new drug A drug company needs to test a new drug. Participants in an experiment are randomly given either the drug or a placebo. If the experiment conducted is double-blind, then… The participants are blindfolded when they take the drug or placebo. The participants do not know whether they are taking the drug or a placebo. Neither the participants nor the drug company executives know which volunteers are taking the drug and which the placebo. Neither the participants nor the evaluators know which volunteers are taking the drug and which the placebo.

A survey is mailed to 1000 voters randomly selected from a county's registered voters asking "Do you support a constitutional amendment to ban abortion?" 235 are returned, and of these 180 respond "yes." What’s the biggest source of bias? Nonresponse

A magazine publisher mails a survey to every subscriber asking about the quality of its subscription service. From which of the following is this study most likely to suffer? A)Undercoverage B) Nonresponse bias C) Sampling bias D) Both nonresponse bias and undercoverage E) Both undercoverage and sampling bias

Our class is numbered from 1 to 30 Our class is numbered from 1 to 30. Who are the first three numbers to be chosen according to this random number table? 36574 47386 09127 55627 9, 12, 27

Our class is numbered from 1 to 500 Our class is numbered from 1 to 500. Who are the first three numbers to be chosen according to this random number table? 36574 47382 09627 45697 365, 209, 456

Retrospective or Prospective A study found that nearly 90% of all child patients with asthma developed pneumonia in their teens. A study found that nearly 90% of teens with pneumonia had asthma as a child. Prospective Retrospective

What is the sampling frame? I am going to do a survey of patients in a nearby hospital. I want to ask O’Connor students their opinion on off campus lunches. I want to ask Arizona residents their opinion on gun laws.

What is a placebo?