Lesson Three: Describing Quantitative Data (Shape & Center)

Question 1

Histogram:

Answer 1

A graph to visualize data from statistical studies.

Steps to create in Excel:
1. Enter the data in excel, each point in its own cell.
2. Highlight the data.
3. Go to the insert tab and select “histogram” from the charts section. Select the first option.
4. Select the graph and click the format button on the top taskbar. In the upper left corner, select horizontal category axis. Then click format selection.
5. Options will open, you can adjust the bin width or # of bins.

Question 2

Bins:

Answer 2

The bars in a histogram that represent data.

Question 3

Symmetric or Bell Shaped Graph:

Answer 3

Both the left and right side of the distribution appear to be a rough mirror image of each other.

Question 4

Right Skewed Graph:

Answer 4

If a histogram of the distribution shows a long right tail. Occurs if there’s large outliers on the right side of the distribution.

Question 5

Distribution:

Answer 5

The overall shape the data makes on the graph.
Also, the way the data is laid out.

Question 6

Left Skewed Graph:

Answer 6

If a histogram of the distribution shows a long left tail. Occurs if there’s large outliers on the left side of the distribution.

Question 7

Unimodal Distribution:

Answer 7

If a distribution has only one peak overall shape.

Question 8

Uniform Distribution:

Answer 8

If there’s a relatively flat shape and no distinct peak, this is a uniform distribution.

Question 9

Bimodal Distribution:

Answer 9

If there are two relatively distinct peaks at the same height.

Question 10

Multimodal Distribution:

Answer 10

If there are more than two peaks at the same height.

Question 11

Center of a Distribution or Mean:

Answer 11

The average, or exact center of the data laid out on the graph or in the chart. Also called the mean.

Formula: Add all data together, then divide it by how many pieces of data were added.

Excel Formula: =average()

Question 12

Sample Mean:

Answer 12

The mean of the sample data.

Symbol: x with a line on top, called the x-bar.

Formula: Add all data together, then divide it by how many pieces of data were added.

Excel Formula: =average()

Question 13

Median:

Answer 13

The middle value in a sorted data set.

Formula: Sort the values from smallest to largest.

If there’s an odd # of values, the median is the middle value.

If there’s an even # of values, the median is the mean of the two middle values.

Excel Formula: =median()

Question 14

Mode:

Answer 14

The most frequently occurring value.

Formula: Find most occurring values.

Sometimes there’s more than one. That’s ok!

Excel Formula: =mode() or =mode.sngl() (for just one mode)
If you get #N/A, it means there’s no mode and only one set of each value in the data set.

Question 15

Statistic:

Answer 15

A number that describes a SAMPLE.

Question 16

Parameter:

Answer 16

Any number that describes a POPULATION.