GGSO Invitational — Experimental Design

Flipping a coin 10 times and getting 7 heads and 3 tails are cause for questioning whether the coin is fair.

Flipping a coin 1000 times and getting 600 heads and 400 tails is cause for questioning whether the coin is fair

Name the statistics law/principle(s) that was used to answer the two questions above

A thermometer reads the temperature in a refrigerator 10 times and yields the following values in degrees Celsius: 39.1, 39.4, 39.1, 39.2, 39.4, 39.1, 39.2, 39.2, 39.1. The true temperature in the refrigerator is 36 degrees Celsius. Which of the following best describes the thermometer?

Which of the following is a difference between bar charts and histograms? Select all that apply.

The following stemplot shows the monthly sales of a certain game at two different companies over a 16 month period. Which of the following statements is true?

You have a sample of apples with weights, in pounds, of 3, 3, 7, 9, and 13. After weighing all of them and calculating the mean, standard deviation, and variance, you realize that you scale is broken and the weights you recorded are actually 3 pounds less than the actual weight of each apple. Which of your calculated values will change? Select all that apply

Which of the following histograms has the largest standard deviation?

Which of these is the best way to reduce response bias?

A sample has median 5, first quartile 3, third quartile 8, and mean 7. Which of the following values are outliers? Select all that apply.

At a certain grocery store, 150 people were randomly selected to construct the 99% confidence interval for the difference in mean checkout time between using the express lane and using self-checkout, which was found to be (-3.78 min, 0.0492 min). Is the difference in mean wait time statistically significant? Why or why not?

To construct a one-sample confidence interval, why is it necessary for the sample size to be greater than 30?

You are trying to help a friend find some sounds to listen to so they can fall asleep. Which type of noise would you not recommend?

In A/B testing, a common source of error is “alpha error inflation.” How can this be avoided?

Given a standard normal distribution curve, what is the area between Z=1.5 and Z=2.4?

In 2017, the class average for the AP Statistics final was 27 with a standard deviation of 5. Your friend scored a 35. In 2018, the class changed the grading system, so the class average was 70 and the standard deviation was 8. You scored an 82. Comparing your score with your friend’s, who had the better performance?

A certain restaurant has arrivals that follow a Poisson process. The expected number of people that arrive between 12-1 each day is 4. What is the probability that there are exactly 3 arrivals between 12 and 1 at the restaurant tomorrow?

To test the hypothesis that the difference between the means of two groups is zero, which test would you use?

A hypothesis test is conducted with a significance level of 0.05. If the p-value of the test statistic is 0.07, what do we do with the null hypothesis?

You measure the height of a sand castle as 2.00 +/- 0.03 ft. Your friend adds a flag on top with a measured height of 0.88 +/- 0.04 ft. What is the uncertainty of the total height of the sand castle (initial height + flag’s height) in ft?

You are trying to find the volume of a cube, so you decide to calculate it by measuring one side. You measure one side as 2.00 +/- 0.02 cm. What is the uncertainty of the volume (in cm³)?

Let's say you measure three values x, y, and z. x = 200 +/- 2, y = 50 +/- 2, and z = 40 +/- 2, where the three uncertainties are independent and random. Find the quantity q = x/(y-z) with the correct number of significant figures.

Let's say you measure three values x, y, and z. x = 200 +/- 2, y = 50 +/- 2, and z = 40 +/- 2, where the three uncertainties are independent and random. Find the uncertainty of the quantity q = x/(y-z) with the correct number of significant figures.

When looking at a residual plot for a least-squares regression line, the line is most likely an appropriate model for the data when the residual plot displays the same pattern as the data.

The covariance of the weight and height of zebras is:

If X and Y are independent, then their covariance is 0.

If X and Y have a covariance of 0, then they are dependent.

Correlation measures the ____ of the linear relationship between two variables.

Correlation is often preferred over covariance to make comparisons easier.

A correlation of 2 indicates: