Measures of Central Tendency
What are the three measures of central tendency?
Mean, Median, Mode
Find the range of this data set: 17, 47, 26, 2, 31, 19
45
What is the five number summary that's needed to make a box-and-whisker plot?
Minimum, 1st quartile, median, 3rd quartile, maximum
This Stem and Leaf plot has ______ items of data.
Ages of Parents | |
Stem | Leaf |
3 | 1 4 4 9 |
4 | 0 0 0 1 2 3 5 7 |
5 | 2 3 |
Key: 3 1 = 31 years old
14
A student writes down the brand names of phones owned by classmates.
What type of data is this?
Categorical
Find the mean rounded to the nearest tenth: 17, 26, 37, 22, 30, 19, 21
24.6
To maintain quality control in a soda factory, every 20th bottle of root beer coming off the production line was open and tested.
This is an example of ________ sampling method.
What is Systematic?
What are the minimum and maximum values of the data set: 78, 12, 109, 36, 121
12 and 121
What is the mode of the time students took to complete their homework, according to this stem and leaf chart.
Time to Complete Homework | |
Stem | Leaf |
3 | 2 2 2 2 2 2 4 |
4 |
|
5 | |
6 | 9 |
7 | 6 8 |
8 | 4 |
Key: 3 2 = 32 minutes | |
What is 32 minutes.
The shirt sizes (S, M, L, XL) of players on a team are listed.
What type of data is this?
Categorical and Ordinal
Find the median: 197, 56, 203, 79, 145, 2
112
The ages (in years) of students in a science club are:
12, 13, 14, 14, 15, 16, 16, 17, 18
Find the Interquartile Range (IQR) of the data.
3
What is the median of the data set: 72, 90, 84, 76, 68
76
Ms. Jackson's Quiz Scores as percentages.
Stems | Leaves |
6 | 3 6 |
7 | 2 9 |
8 | 4 7 7 |
9 | 0 0 1 1 3 3 3 |
| |
The mean is______. (round to the nearest whole number)
What is 84%.
A teacher selects every 5th student from the class roll to participate in a survey.
What type of sampling method is this?
Systematic Sampling.
What value of x makes this data set have a mean of 6: 10, 6, 12, 3, x
5
The range of each data set: 30, 27, 24, 30, 32, 31
What is 8?
Find the five number summary: 27, 22, 25, 27, 23, 28
Min = 22
Q1 = 23
Medium= 26
Q3 = 27
Max = 28
Draw a graph to represent positively and negatively skewed.
Teacher check for acuracy
You want to survey students across all year levels in your school to get balanced feedback. What sampling method would ensure fair representation from each year level?
Stratified Sampling
Create a data set that has 5 values, has a mean of 12, a median of 13 and a mode of 13 and 14.
6, 13, 13, 14, 14
Find the standard deviation of the data set: 63, 59, 70, 68
4.3
The following are the scores out of 100 from 15 students on their final maths exam:
56, 62, 65, 67, 68, 70, 71, 74, 75, 78, 81, 83, 85, 88, 93.
Identify any outliers, if they exist.
No outliers
Find the Five number summary for both graphs in the image.
| French | German | Spanish | Total |
Female | 15 | 11 | 13 | 39 |
Male | 16 | 17 | 8 | 41 |
Total | 31 | 28 | 21 | 80 |
A school has 800 students. The administration wants to survey student opinions on a new school uniform policy. They know that opinions may differ significantly by year group and gender. To ensure the sample reflects the entire student population fairly, the school decides to group students by year group (Years 7–12) and by gender (male/female/other). From each subgroup, they randomly select 10% of students to participate in the survey.
a) What type of sampling method is being used?
b) Explain why this method is more appropriate than simple random sampling in this case.
a) Stratified Random Sampling
b) Teacher review