Data Science Statistical Concepts and Analysis 3

Question 1

Which sampling method gives every member of a population an equal chance of selection?

Accepted Answer

Simple random sampling

Answer

Convenience sampling

Answer

Quota sampling

Answer

Snowball sampling

Question 2

The standard deviation measures:

Accepted Answer

The typical spread of values around the mean

Answer

The middle value of a dataset

Answer

The most frequent value

Answer

The difference between max and min

Question 3

In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?

Accepted Answer

68%

Answer

50%

Answer

95%

Answer

99.7%

Question 4

Which is an example of a categorical (nominal) variable?

Accepted Answer

Eye color

Answer

Temperature in Celsius

Answer

Annual income

Answer

Height in centimeters

Question 5

If two events are mutually exclusive, then:

Accepted Answer

They cannot occur at the same time

Answer

They are independent

Answer

Their probabilities multiply

Answer

They always occur together

Question 6

What does R-squared represent in a regression model?

Accepted Answer

The proportion of variance in the outcome explained by predictors

Answer

The slope of the regression line

Answer

The correlation between residuals

Answer

The number of predictors used

Question 7

A boxplot's interquartile range (IQR) spans which values?

Accepted Answer

The 25th to the 75th percentile

Answer

The minimum to the maximum

Answer

The 10th to the 90th percentile

Answer

The mean plus or minus one SD