What does an R-squared value of 0.80 indicate?
80% of the variation in the dependent variable is explained by the independent variable.
20% of the variation in the dependent variable is explained by the independent variable.
The correlation between the variables is 0.80.
The slope of the regression line is 0.80.
What is the purpose of calculating a correlation coefficient?
To predict the value of one variable based on the value of another variable.
To test the significance of the difference between two means.
To determine the cause-and-effect relationship between two variables.
To measure the strength and direction of the linear relationship between two variables.
What is the primary purpose of inferential statistics?
To make generalizations about a population based on a sample.
To describe and summarize data.
To visually represent data using graphs and charts.
To organize and clean raw data.
Which component of a time series reflects long-term changes in the data over time?
Cyclical Variation
Trend
Irregularity
Seasonality
A 95% confidence interval for a population mean is calculated to be (60, 80). What is the correct interpretation of this interval?
There is a 95% probability that the true population mean falls between 60 and 80.
If we were to repeatedly construct confidence intervals using this method, 95% of them would contain the true population mean.
If we were to repeatedly sample from this population, 95% of the time the sample mean would fall between 60 and 80.
We are 95% confident that the sample mean falls between 60 and 80.
When is it appropriate to use a one-tailed hypothesis test?
When the sample size is small.
When the data is not normally distributed.
When you are only interested in detecting a difference in one direction.
When you want to test for a difference in either direction.
The number of cars passing a certain point on a highway averages 10 per hour. What is the probability that exactly 15 cars pass that point in a given hour?
0.0347
0.25
0.15
0.5
When would you use a paired t-test instead of an independent t-test?
When comparing the means of the same group before and after a treatment.
When comparing the means of two groups with unequal variances.
When comparing the means of two independent groups.
When comparing the means of three or more groups.
What is the primary goal of factor rotation in factor analysis?
To improve the interpretability of factors
To calculate the eigenvalues of factors
To increase the communalities of variables
To reduce the number of factors
The lifetime of a certain electronic component follows an exponential distribution with a mean of 10,000 hours. What is the probability that a randomly selected component lasts less than 5,000 hours?
0.6321
0.3935