Populations and Samples
What is a population in statistics?
The entire group being studied
How do you find the mean of a data set?
Add all numbers and divide by the count
How do you calculate range?
Subtract the smallest value from the largest value
What five values are shown in a box plot?
Minimum, Q1, Median, Q3, Maximum
How is a histogram different from a bar graph?
A histogram groups data into ranges/intervals
What is a sample in statistics?
A subset of a population
What is the median of the following numbers: 3, 7, 9, 15, 17?
9
What does a large range tell you about a data set?
The data values vary widely
What does the length of the box in a box plot represent?
The interquartile range (IQR)
What does the height of a bar in a histogram represent?
The frequency of data in that range
Why do researchers use samples instead of entire populations?
It saves time and resources
What is the mode of the numbers: 5, 8, 8, 10, 12, 12, 12, 15?
12
If a data set has a range of 25 and a minimum value of 10, what is the maximum value?
35
What does the line in the middle of the box on a box plot represent?
The median
There are no _______ in histograms
Gaps
Give an example of when a sample is used to make an inference about a population.
A survey of 100 students to represent an entire school
Which measure of central tendency is most affected by extreme values?
The mean
How does an outlier affect the range?
It increases the range significantly
What does the median tell us in a box plot?
The middle value of the data)*
What type of table needs to be created before you create a histogram?
Frequency table
What is the difference between a random and biased sample?
A random sample represents the population fairly, while a biased sample does not
Explain why the median is a better measure than the mean for a skewed distribution.
The median is not affected by extreme values
Find the mean, median, mode, and range of the following data set: 4, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12,14,15, 19
Mean: 135/14= 9.64
Median: 9.5
Mode: 4, 11
Range: 15
What percentage is each section of a box plot?
25%
If the majority of the data on the right hand side of the histogram, the data is skewed...?
Left