Unit 3 LA Check-in Quiz

Suppose the population variance is σ2=25σ2=25. Then

σ=5

In a sample of 20 friends, 12 have blue eyes. The sample proportion of blue eyes is:

60%

The mean of 6, 13, and 5 is:

8

Suppose you have 4 observations: 9, 6, 15 and 10. The median is ___.

9.5

A set of observations either has no mode, or multiple modes.

False

In a left-skewed distribution, the median is less than the mean.

False

The mean is always equal to one of your data values.

False

The median is sensitive to outliers.

False

The median tells you something about the amount of variation in your observations, but the mean does not.

False

The sample variance can be negative.

False

The range is based on 2 observations in your data.

True

The sample mean is based on fewer observations than the population mean.

True

The sample standard deviation is s=1.5s=1.5. This implies that σ2σ2 is equal to

Unknown

Suppose you have a sample of 11 observations. The median is ______ in the ordered list.

the 6th observation

Suppose that the population had a 5th observation, x5=12x5=12, in addition to the observations in the table above. The variance is then ____.

4.8

Suppose you have a population with N = 3 observations and x1=x2=x3=5x1=x2=x3=5. The population variance is:

0

In a sample of 50 people, the proportion of those with blue eyes is 32%. How many people in the sample have blue eyes?

16

Suppose that x1 = 5, x2 = 3, x3 = 1, x4 = -2 and x5 = 4. Then ∑5i=3xi∑i=35xi is equal to

3

In a symmetric frequency distribution, the mean and median are equal.

True

The median of a set of observations is the ____ value.

middle