#1
What is the median of the following set of numbers: 3, 6, 9, 12, 15?
#2
Which measure of central tendency is most affected by outliers?
#3
What is the probability of rolling a prime number on a fair six-sided die?
#4
Which of the following is NOT a measure of dispersion?
Range
Variance
Standard Deviation
Median
#5
In a statistical experiment, what does 'random sampling' refer to?
Selecting a subset of individuals from the population without replacement
Selecting a subset of individuals from the population with replacement
Ensuring every individual in the population has an equal chance of being selected for the sample
Selecting individuals from the population based on a specific characteristic
#6
What is the formula for calculating standard deviation?
√(Σ(xi - x̄)² / N)
Σ(xi - x̄) / N
Σ(xi - x̄)² / (N - 1)
Σ(xi - x̄) / (N - 1)
#7
In a normal distribution, what percentage of data falls within one standard deviation from the mean?
#8
What is the formula for calculating the z-score of a data point?
(x - μ) / σ
(x - μ) * σ
(x - σ) / μ
(x - μ) / σ²
#9
What does the p-value represent in hypothesis testing?
The probability of rejecting a true null hypothesis
The probability of accepting a false null hypothesis
The probability of obtaining the observed results, or more extreme, assuming the null hypothesis is true
The probability of obtaining the observed results, or less extreme, assuming the null hypothesis is true
#10
What is the formula for calculating the coefficient of determination (R-squared) in linear regression?
1 - (Σ(yi - ŷi)² / Σ(yi - ȳ)²)
Σ(yi - ŷi)² / Σ(yi - ȳ)²
1 - (Σ(yi - ȳ)² / Σ(yi - ŷi)²)
(Σ(yi - ŷi)² / Σ(yi - ȳ)²) - 1
#11
What is the formula for calculating the coefficient of variation?
(Standard Deviation / Mean) * 100
(Mean / Standard Deviation) * 100
(Range / Mean) * 100
(Mean / Range) * 100
#12
What is the formula for calculating the covariance between two variables X and Y?
Σ(xi - x̄) * Σ(yi - ȳ) / N
Σ(xi * yi) / N
Σ(xi - x̄) * Σ(yi - ȳ) / (N - 1)
Σ(xi * yi) / (N - 1)
#13
What is the formula for the probability density function (PDF) of a normal distribution?
(1 / (σ * √(2π))) * e^(-((x - μ)² / (2σ²)))
(1 / √(2πσ)) * e^(-((x - μ)² / (2σ²)))
(1 / (σ * √(2π))) * e^(-((x - μ) / (2σ)²))
(1 / (2πσ)) * e^(-((x - μ)² / (2σ)²))
#14
What is the formula for the confidence interval of the population mean with a known population standard deviation?
(x̄ ± (z * (σ / √n)))
(x̄ ± (t * (σ / √n)))
(x̄ ± (z * (s / √n)))
(x̄ ± (t * (s / √n)))
#15
What is the formula for calculating the harmonic mean?
N / Σ(1 / xi)
Σ(xi) / N
N / Σ(xi)
Σ(1 / xi) / N