Lab 1

Which of the following formulas describes the sample mean?

• 
• 
• 
• None of the other answers.

If two events A and B are disjoint, the probability that either event A or event B takes place is given by...

• P(A∩B)=P(A)*P(B)

• P(A∪B)=P(A)+P(B)

• P(A∪B)=P(A)+P(B)−P(A∩B)

• P(A)=1−P(A^c))

True or False - Hair colors are an example of a nominal variable.

• True

• False

Which statistics can you calculate on a ratio scaled variable?

• mean

• mode

• chi-square

• all of them.

How do you calculate the range of a variable?

• 75th - 25th percentile value

• highest - smallest observation value

• rank observations according to value and find the middle

• the range is calculated by using a t-distribution

A standard deviation tells you how "normal" an observed value is compared to the mean of a distribution.

• True

• False

A left-skewed distribution has more observations left of the mean.

• True

• False

Tests for relationships between variables (t-tests, correlations, regressions) are examples of descriptive inference.

• True

• False

How many modes has this distribution?

• 1

• 2

• 0

• can't be determined from the graph.

Which of the following statements is true?

• The median value for London is approx. 55% of voting remain

• The outliers for Wales mean that data points are outside of the IQR

• 25% of the distribution for England is between 44 and 49% of voting remain

• The 1st percentile for Scotland ends at approx. 51% of voting remain