Exploring Data
The mean and the median are close together.
What is a symmetric distribution?
Fraction of the variation in the values of y that is accounted for by the LSQR line of y on x.
What is the coefficient of determination (r2)?
Gather information about individuals as they are
What is an observational study?
Set of all possible outcomes
What is the sample space?
A consumer organization was concerned that an automobile manufacturer was misleading customers by overstating the average fuel efficiency (measured in miles per gallon, or mpg) of a particular car model. The model was advertised to get 27 mpg. To investigate, researchers selected a random sample of 10 cars of that model. Each car was then randomly assigned a different driver. Each car was driven for 5,000 miles, and the total fuel consumption was used to compute mpg for that car. How would the consumer organization analyze the data?
What is a one-sample T-test?
Joey's first 14 quiz grades: 86, 84, 91, 75, 78, 80, 74, 87, 76, 96, 82, 90, 98, 93. The number 85.
What is Joey's mean quiz score (x_bar)?
Rate at which the predicted response y_bar, changes as the explanatory variable x changes
What is the slope of the regression line (b)?
Combinations of the explanatory variable (treatments) are imposed on
What is an experimental unit or a subject (if humans)
P(A and B) = 0
What is two mutually exclusive events?
A recent report stated that less than 35 percent of the adult residents in a certain city will be able to pass a physical fitness test. Consequently, the city’s Recreation Department is trying to convince the City Council to fund more physical fitness programs. The council is facing budget constraints and is skeptical of the report. The council will fund more physical fitness programs only if the Recreation Department can provide convincing evidence that the report is true. The Recreation Department plans to collect data from a sample of 185 adult residents in the city. Which test of significance will be conducted at a significance level of α = 0.05 to help the council make a decision?
What is a One Proportion z-test?
Allow us to examine location within a distribution
What is A cumulative relative frequency graph?
sample mean x= 1.75%, sample std x= 5.36%, sample mean y = 9.07%, sample std y = 15.35%, r = 0.596. The LSRQ.
What is predicted y = 1.7 x + 0.0609?
All experimental units are assigned completely by chance.
What is a completely randomized design?
Multiplication rule for independent events
What is P(A and B) = P(A) P(B)
A taxicab company in a large city charges passengers a flat fee to enter a cab plus an additional fee per mile. There is also a charge for time spent stopped in traffic. The company wants to develop a new method for determining fares based on mileage and a flat fee only, not on time spent stopped in traffic. A random sample of 10 recent cab fares was selected, and the distance, in miles, and the fare, in dollars, were recorded. A regression model was fit to the data, and the output, scatterplot, and residual plot are given below. Estimate the slope of the least squares regression line. Assume the conditions for inference are met.
What is a linear regression t-interval?
The mean salary of all female workers is $35,000. The mean salary of all male workers is $41.000. A number between $35,000 and $41.000.
What is the mean salary for all the workers?
Measurements of children in Mumbai found a LSQR for predicting height (y) from arm span (x): y_hat = 6.4 + 0.93 x. A sample child 59 cm tall and arm span 60 cm. The residual.
What is -2.2 cm?
The four principles of experimental design
What is comparison, random assignment, control, replication?
Select an adult at random. Define A: a person has earned a college degree, and T: a person's career is teaching. Rank from smallest to largest: P(A), P(T), P(A|T), and P(T|A)
What is P(T)<P(T|D)<P(D)<P(D|T)?
A student measured the heights and the arm spans, rounded to the nearest inch, of each person in a random sample of 12 seniors at a high school. A scatterplot of arm span versus height for the 12 seniors and computer output is shown below. Is there statistically convincing evidence that arm span is related to height?
What is linear regression t-test?
Always on or above the horizontal axis and has exactly area of 1
What is a density curve?
The study described in the previous question found that children who watch more television tend to have lower reading scores than children who watch fewer hours of television. The study report says that, “Hours of television watched explained 9% of the observed variation in the reading scores of the 125 subjects.” The correlation.
What is 0.3?
Reason to take random samples from the population
What is inference about the population?
40% of the students are REGISTERED to vote. 60% of those prefer candidate A and 40% prefer candidate B. 60% are NOT REGISTERED to vote. 30% prefer candidate A and 70% prefer candidate B. if there are 10 REGISTERED voters, what is the probability of getting 2-5 (two to five) votes for candidate B?
What is P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.787404 ?
A researcher believes that treating seeds with certain additives before planting can enhance the growth of plants. An experiment to investigate this is conducted in a greenhouse. From a large number of Roma tomato seeds, 24 seeds are randomly chosen and 2 are assigned to each of 12 containers. One of the 2 seeds is randomly selected and treated with the additive. The other seed serves as a control. Both seeds are then planted in the same container. The growth, in centimeters, of each of the 24 plants is measured after 30 days. These data were used to generate the partial computer output shown below. Graphical displays indicate that the assumption of normality is not unreasonable. Estimate the mean difference in growth, in centimeters, of the plants from the untreated and treated seeds.
What is matched pair t-interval?