stats 5

There are 30 students in Alice's math class. If the students' marks on the last test exhibit a normal distribution, and the average grade was 75%, then how many students scored within one standard deviation of 75%?

20

What is the minimum number of samples that should be used for a confidence interval calculation using a Z-value statistic?

30

Find the first quartile for the following data set: 7, 9, 13, 4, 18, 3, 9, 10, 15, 8, 2, 6, 9

5

Find the interquartile range for the following data set: 7, 9, 13, 4, 18, 3, 9, 10, 15, 8, 2, 6, 9

6.5

A decile can be defined as _____.

A quantile that groups the data into 10 equal frequencies

The most fundamental purpose of an index in business is to facilitate:

Accurate comparisons and benchmarks

The design of a product is causing quality control issues. This is an example of a which type of cause?

Common

Which of the following situations is best modeled by a discrete random variable?

Drawing cards from a deck, and calculating the probability of drawing a certain hand.

The numbers on lacrosse jerseys are an example of _____ data.

Nominal

In the z-test formula, what does n stand for?

Sample size.

A data set in which all the values are very close to the mean value would have a small _____.

Variance

A dot plot is a visual representation of data using intervals or categories of variables, with each dot representing _____.

an observation in the data

A quantitative method that uses data from past periods is called _____.

time series forecasting

What is the method that requires selecting samples based on a system of intervals in a numbered population?

Systematic random sampling

Which of the following best describes why the correlation coefficient is important?

The correlation coefficient describes the relationship between the two variables.

Which of the following is a fixed or discrete data point, rather than continuous?

The number of checked bags on flight 329.

What does normality mean in analyzing residuals?

The residuals are normally distributed around the line of best fit.

In hypothesis testing, data that falls into the critical region is used for what purpose?

To reject the null hypothesis

Which of the following statements BEST explains why one might utilize the confidence interval?

You want to quantify your confidence in a conclusion derived from a sample.

If you needed to know how individual sales values compare against the average sales and the standard deviation, which measure will you use?

Z-Score

Time series analysis is LEAST helpful in forecasting and predictive applications when the _____.

data is a random sample or measured at random intervals over time.

A manager has collected data that looks at how many bugs are in the programs his company produces each day. The company produces different numbers of programs each day, and some programs have several bugs. The best choice is for the manager to use a(n) _____ chart.

u

How is the standard correlation coefficient derived?

By using the differences between those individual values and their averages

What is a straight line that attempts to predict the relationship between two points, also known as a trend line or line of best fit?

Regression line