Lesson 4: Center, spread, and shape of distributions

What is the mean in a data set?

The average number

What is the median in a data set?

The middle number

What is the mode in a data set?

The most common number

How do you find the mean in a data set?

Sum of values/number of values

4, 3, 1, 6, 1, 7

What’s the mean of this data set? (answer will be a repeating decimal)

3.6

4, 3, 1, 6, 1, 7

What’s the median in this data set? (answer will be a decimal)

3.5

4, 3, 1, 6, 1, 7

What’s the mode in this data set?

1

1.25 pets per student

What is the median in an odd amount of set numbers?

The middle value

What is the median in an even amount of set numbers?

The average of the 2 middle values (aka adding the two middle numbers and dividing it by 2)

What should you do to a set of numbers when finding a median?

Re-arrange the numbers in numerical order (smallest to biggest)

9, 7, 12, 5, 9

What’s the median?

9

2, 5, 6, 7, 7, 10

What’s the median?

6.5

When does a data set have no mode?

If no number appears more than the other

Is it possible for a number set to have more than one mode?

Yes

1, 1, 2, 3, 3, 3, 3, 3, 8

What’s the mode?

3

What’s the mean? (Sum of all of it is 42 to save you some time)

6

What’s the median?

5

What’s the mode?

5

How do you find the range of a data set?

Subtract the largest number by the smallest number

What is the standard deviation of a number set?

The square root of the variance

1, 9, 4, 3, 8

What’s the range?

8

2nd line

What’s the range for Jazmin’s time?

30 minutes

What’s the range for Pablo’s time?

120 minutes

Both people practiced 45 mins a day. Is the standard deviation of Jazmin’s practice times smaller or larger than Pablo’s practice times?

Smaller

What was the initial mean and what was the mean after the lowest score was removed?

Initial mean: 90.4

Mean after: 93

What was the initial median and what was the median after the lowest score was removed?

Initial: 92

After: 93

What is an outlier?

A number in a data set that’s very different from the other numbers

3, 5, 7, 7, 7, 10, 100

What’s the outlier?

100

Does an outlier affect a mean or median more?

Mean

What happens to the mean and median when a large outlier is removed?

The mean will decrease, while the median may decrease or stay the same

What happens to the mean and median when a small outlier is removed?

The mean increases, while the median may increase or stay the same

A range of numbers include 5, 2, ?, 2, 4, 8 and the mean is 4. What’s the missing number?

3

A range of numbers include 20, 20, 40, 60, x and the mean is 30. What does x equal?

10

124 miles