#1
What is the median of the following set of numbers: 5, 8, 12, 16, 20, 22, 25?
#2
What is the mode of the following set of numbers: 4, 6, 8, 8, 10, 12, 12, 12, 14?
#3
What does 'standard deviation' measure in statistics?
The spread of data values
The average of data values
The most frequently occurring value
The difference between the largest and smallest values
#4
In a normal distribution, approximately what percentage of data falls within one standard deviation from the mean?
#5
Which of the following is not a measure of central tendency?
#6
In statistics, what does 'null hypothesis' refer to?
A hypothesis that states there is no significant difference or relationship between variables
A hypothesis that states there is a significant difference or relationship between variables
A hypothesis that states there is a 50% chance of an event occurring
A hypothesis that states there is no variability in the data
#7
What is the formula for calculating the z-score of a data point in a normal distribution?
(x - μ) / σ
(x - σ) / μ
(σ - x) / μ
(μ - x) / σ
#8
What is the formula to calculate the variance of a sample?
(Σ(x - μ)²) / (n - 1)
(Σ(x - μ)²) / n
Σ(x - μ)
(Σ(x - μ))² / n
#9
What is the purpose of a p-value in hypothesis testing?
To determine the strength of the relationship between variables
To measure the effect size
To determine the probability of obtaining the observed results if the null hypothesis is true
To establish causation between variables
#10
What does the coefficient of determination (R-squared) represent in regression analysis?
The slope of the regression line
The percentage of the total variation in the dependent variable explained by the independent variable(s)
The intercept of the regression line
The standard deviation of the residuals
#11
What is the purpose of a confidence interval in statistics?
To determine the statistical significance of a hypothesis test
To estimate the range within which a population parameter is likely to lie
To calculate the effect size of an experiment
To measure the strength of the relationship between variables
#12
What is the formula for calculating the probability of an event A given event B, P(A|B), using the conditional probability formula?
P(A) * P(B)
P(A) + P(B)
P(A) / P(B)
P(A) - P(B)