Final Exam Practice

Flashcards for MAT118 Spring 2025 Final Exam Practice Short Answer Solutions

What is the formula for calculating a 95% confidence interval for a population proportion?

𝑝̂± 2 × sqrt((𝑝̂(1-𝑝̂))/n)

If a sample includes only students passing by the library, is this a simple random sample of all DCC students?

No, because not every student has the same chance of being chosen.

In the chimpanzee study, what is the parameter of interest denoted by?

The long-run proportion of times Sarah would pick the correct photo, denoted by π.

In the chimpanzee study, if the null hypothesis is that Sarah is just guessing, what is the appropriate symbolic representation?

H0: π = 0.5

In the chimpanzee study, how do you calculate the p-value from the null distribution?

Divide the number of dots that have results as extreme as or more extreme than the study results by the total number of dots.

In the chimpanzee study, what does a single dot in the null distribution represent?

The number of correct choices Sarah made in 8 attempts, assuming she is picking a photo at random.

When identifying components of research questions, what are observational units?

The individual entities about which information is recorded (e.g., college students, Dutchess County residents).

How are explanatory and response variables classified?

Categorical or quantitative.

When investigating whether teenagers in the UK read more Harry Potter books than in the US, should you use random sampling or random assignment?

Ideally, random sampling would be used to generalize results to all teenagers in those countries.

What are some examples of categorical variables you could collect from colleges?

Whether it’s a private or public school, two-year or four-year school, and whether it offers graduate degrees or a statistics major.

What are some examples of quantitative variables you could collect from colleges?

The number of students enrolled, the cost of tuition, annual revenue, and number of dorms.

What is the null hypothesis in symbols for testing if the average amount spent on Halloween is $53?

H0: μ = 53

What does a t-score measure in relation to the null distribution?

The number of standard deviations the observed sample statistic is above or below the center of the null distribution.

If a study requires randomly assigning people to have children or not, is this a realistic design?

No, it would not be realistic.

What is a 90% confidence interval based on repeated tests of significance?

Null hypothesized values of π that have a p-value greater than 0.1.

In the study with praise, what type of study was it?

Experiment

Can you draw a cause and effect conclusion from an experiment?

Yes

What is the alternative hypothesis in symbols for testing if the proportion of all receivers who pick the correct image is greater than 0.25?

Ha: π > 0.25

How do you calculate a Z-score?

(sample proportion - population proportion) / standard deviation