Review for Statistical Methods Exam 1(1)

What are the four steps involved in statistics according to the course?

1. State the problem 2. Plan the specific statistical work needed 3. Solve the problem by making the necessary graphs and calculations 4. Draw conclusions

What is the first step to begin data analysis?

A. Graphing the data and constructing numerical summaries

How should we study the reasons that students binge drink?

C. Do a survey of students, asking about binge drinking and their reasons for doing so.

Which statement about variation is true?

B. Variation is common in datasets.

What is the process of drawing conclusions about the greater world based on a sample called?

B. Statistical inference.

What is the most appropriate graph for a small quantitative dataset such as exam scores?

C. a stem plot.

What type of variable is 'region' when classifying radio stations in a survey?

A. Categorical, because region divides radio stations into groups.

What type of variable is the health insurance status coded for employees?

A. Categorical.

What does the histogram of age for horses in the enteroliths study appear to be?

A. Slightly right-skewed.

What is the difference between a histogram and a bar chart?

D. A bar chart displays a categorical variable on the x-axis, whereas a histogram does not.

What can be inferred about the five-number summary of test scores provided?

C. There are no suspected outliers.

What are the mean and median of the ages of pennies, rounded to the nearest tenth?

A. 10.3 and 9.5.

What is the cutoff for a high outlier among the reported times spent on social media?

B. 117.

What are the first and third quartiles of the faculty members' ages calculated from a stem plot?

D. 39 and 58 years.

For a density curve with a long left tail, which statement is true?

C. mean < median.

What running time would place a student in the top 1% of runners based on the given mean and standard deviation?

B. 134.2 seconds.

What score on the Wechsler Adult Intelligence Scale corresponds to the highest 10% of scores?

A. 125.

What proportion of adults has scores between 80 and 120?

D. 0.82.

Using a standard Normal curve, what is the area corresponding to Z > −1.62?

A. 0.9956.

In the study of income and grocery expenditures, what is the response variable?

B. Weekly expenditure.

What is a plausible value for the new correlation coefficient in a scatterplot of fat content and calories?

A. +0.7.

What can be said about the correlation between automobile brand and quality?

D. Correlation makes no sense here, because brand is a categorical variable.

What does a negative association between bone density and age indicate?

C. As women get older, bone density tends to decrease.

What statement about correlation is correct?

D. Changing the units of measurement of x or y does not change the value of the correlation r.

What is the association between mortgage interest rates and new houses being built based on the data?

B. Negative.

What is the residual for an employee whose current salary is significantly higher than predicted?

C. $2,252.70.

What is true about the relationship defined by the least squares regression line y = -3 + 3x?

C. The relationship between x and y is positive.

What is the correlation coefficient for the relationship studied between BMI and time spent under the influence of marijuana?

C. -0.366.

What is true about the mean of residuals from least-squares regression?

A. The mean of the residuals from least-squares regression is zero.