Pop for Population
A scientist want to now the average weight of The Pacific Northwest Tree Octopus. He goes out and and weighs 15 Octopi chosen at random from 3 regions of Washington, where the octopus roam. What is the population?
All Pacific Northwest Tree Octopus.
Mr. Hills has a collection of large Lego sets. He randomly selected 25 sets and weighed them to find the average weight for larger Lego sets. Is this sample Biased? Why or why not?
Biased, it is too small of a sample.
This is calculated by putting the numbers of a data set in order, then finding the middle value.
Median.
Find the range of the data set.
3, 4, 2, 12, 18, 5.
The Range is 16
Using chart 2, Mr. Hills will show it to you, what is the range of shopping time for Group A?
The range is 60 minutes.
You want to know the average height of 7th graders in the United states. Should you attempt to use a sample or the whole population?
A sample.
You spend a day asking every third person that comes out of Hannaford if they bought clothing while shopping today. None of them said yes. From that sample you come to the conclusion that no one buys cloths in Belfast. Is your conclusion valid? Why or why not.
It is not valid, because you asked people coming out of a grocery store about buying clothing.
This value is found by adding all of the values in a data set together, then dividing the sum by the number of values.
The Mean
Use the Chart 1 to find the Range of the data set.
The range is 8.
The weights of male and female house cats was scientifically collected. The range of weights for the males was 27 pounds and the MAD for the male weights was 7 pounds. The range of weights for the females was 12 pounds and the MAD for the female weights was 7 pounds. Which gender has the greatest Variation of weights? How do you know?
The males, because the range is much larger.
Four researchers have been collecting data to find the average weight of bottle nosed dolphins. They have found the following averages of weights in pounds: 386, 463, 495, and 456. Using these sample numbers make an estimate of the average weight.
450 pounds.
Mrs. Seekins wants to know how many students in our school charge their computers at night. She asked every 5th student that came into the school building if they remembered to charge their computers last night. She asked 75 students total. Is this biased or unbiased? Why?
It is a unbiased, it is a random sample.
Find the median of the data set.
3, 4, 2, 12, 18, 5.
Median is 4.5
Given the data set, find the Inter Quartile Range.
3, 4, 2, 12, 18, 5.
Inter Quartile Range = 9
Using Chart 2, what is the IQR for Group A?
IQR is 25 minutes.
A scientist want to now the average weight of The Pacific Northwest Tree Octopus. He goes out and and weighs 15 Octopi chosen at random from 3 regions of Washington, where the octopus roam. What is the size of the sample?
45 octopi.
You ask 20 members of the school band about their favorite activity. Chart shows the results. You conclude that band is the favorite activity of 70% of the students in your school. Is this a valid assumption? Why or why not?
This is not valid because the sample was biased.
Find the mean of the data set.
3, 4, 12, 12, 18, 5.
Mean is 9.
Using chart 1, what is the IQR?
The Inter Quartile Range is 5.
Using Chart 2, how do the medians of the two data sets compare?
Group B has a lower median than Group A
Mrs. Seekins wants to know how many students in our school charge their computers at night. She asked every 5th student that came into the school building if they remembered to charge their computers last night. She asked 75 students total. What is the sample? What is the population?
The sample is 75 random students. The populations is the students in your school.
Mrs. Seekins wants to know how many students in our school charge their computers at night. She asked every 5th student that came into the school building if they remembered to charge their computers last night. She asked 75 students total. 35 students said they didn't charge their computers. Mrs. Seekins now thinks that of the 300 students in school 140 students forgot to charge their laptops. Is that a valid assumption?
Yes, 35 x 4 = 140
75 x 4 = 300
so 140 out of 300 is valid.
Use chart 4. A group of three different researchers each weigh 5 randomly selected male coyotes . They want to use these samples to estimate the average weight of male coyotes in the region. The table below shows the weights each researcher recorded. Find the mean weight for each group.
Researcher A - 38
Researcher B - 39
Researcher C - 40
Find the MAD of the data set.
3, 4, 12, 12, 18, 5.
MAD is 5.166 or about 5
A group of three different researchers each weigh 5 randomly selected male coyotes . They want to use these samples to estimate the average weight of male coyotes in the region. Chart 4 shows the weights each researcher recorded. Make an estimate of the average weight of a coyote in the region.
Average weight is 39 pounds.