Which of the following is an example of a non-parametric inferential statistical test?
Chi-square test
z-test
t-test
ANOVA
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?
0.15
0.5
0.25
0.0347
What is the primary difference between simple exponential smoothing and double exponential smoothing?
Double exponential smoothing is used for stationary data, while simple exponential smoothing is used for non-stationary data.
Simple exponential smoothing uses a moving average, while double exponential smoothing uses an autoregressive model.
Double exponential smoothing considers trend, while simple exponential smoothing does not.
Simple exponential smoothing considers seasonality, while double exponential smoothing does not.
Suppose 60% of emails in your inbox are spam and 40% are legitimate. Also, 95% of spam emails contain the word 'free,' while only 1% of legitimate emails do. If an email contains the word 'free,' what's the probability it's spam?
0.004
0.996
0.57
0.05
What does a Pearson correlation coefficient of -0.9 suggest about the relationship between two variables?
Strong negative linear relationship
No linear relationship
Weak positive linear relationship
Strong positive linear relationship
What is the null hypothesis in a Chi-square test of independence?
The two variables are independent.
The two variables are dependent.
The means of the two groups are equal.
The variances of the two groups are equal.
When is Spearman's rank correlation a more appropriate measure of association than Pearson's correlation?
When the variables are measured on an interval or ratio scale and normally distributed
When outliers are not present in the data
When the relationship between variables is perfectly linear
When the relationship between variables is non-linear but monotonic
A 95% confidence interval for a population mean is calculated to be (60, 80). What is the correct interpretation of this interval?
We are 95% confident that the sample mean falls between 60 and 80.
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.
In a binomial distribution, if the probability of success on each trial is 0.3 and there are 10 trials, what is the expected value of the number of successes?
3
5
10
7
When would you use a paired t-test instead of an independent t-test?
When comparing the means of two groups with unequal variances.
When comparing the means of two independent groups.
When comparing the means of the same group before and after a treatment.
When comparing the means of three or more groups.