Ch1
Identify the kind of variable and it's sub-type:
Income
(ch 1 worksheet)
What is quantitative and continuous
sketch a histogram to reflect the following:
a. Unimodal, skewed left
b. Bimodal, symmetric
c. Unimodal, skewed right
d. Unimodal, symmetric
let's check!
5. The weight of 10 offensive linemen were:
312 305 340 320 366 324 309 315 305 305
find the following:
a. Give the Five Number Summary
b. Give the IQR
c. Give the outlier boundaries
d. Are there any outliers? If so, list them.
a. Offensive linemen: min = 305, Q1= 305, med = 313.5, Q3 = 324, max 366
b. 19
c. lower boundary= 276.5
upper boundary = 352.5
d. yes, 366
A botanist wants to compare the effect that two different fertilizers have on plant growth.
She randomly selects 20 plants from a field and applies fertilizer A to them for one week.
She also randomly selects another 20 plants from the same field and applies fertilizer B to them for one week.
After one week she measures the average plant growth for each group.
Explanatory Variable: Type of fertilizer. This is the variable we change so that we can observe the effect it has on plant growth.
Response Variable: Plant growth. This is the variable that changes as a result of the fertilizer being applied to it.
Identify the variable type/sub-type:
Number of siblings
What is quantitative & discrete
Given the data create a stem plot:
108, 109, 109, 113, 117, 118, 118, 118, 119, 121, 122, 126, 130, 140, 151, 158
nicolle pull up example :D
The average number of days absent per student per year at a local high school is 17 days with a standard deviation of
4 days.
Find the z score for a student absent 6 days
z= -2.75
8. identify scatterplot (show image)
8. 1c, 2d, 3a, 4b
Identify the variable type and it's sub-type
Employee ID number
What is qualitative and nominal (identifier)
list out the data for the following split-stem-and-leaf plot
(nicolle pull up example lol)
240, 242, 243, 249, 251, 251, 254, 257, 258, 258, 259, 260, 260, 261, 261, 263, 265, 265, 266, 267, 268, 269
1. The number of cars passing through a bank drive-thru during each 15 minute period was recorded.
The results are shown below:
27, 29, 27, 30, 30, 27, 32, 29, 14, 37, 33,
26, 33, 27, 22, 17, 21, 29, 29, 31, 29, 33
a) Find the mean
b) Find the sample standard deviation
c) Find the 5 number summary
d) Find the IQR
e) Calculate the outlier boundaries
f) Are there any outliers for this dataset?
g) Draw the boxplot
h) Is the distribution skewed or symmetric?
a. 487.4
b. 130.49
c. min=344, Q1=354, med=480.5, Q3=622, max=648
d. 268
e. lower fence = -48,
upper fence = 1024
f. no outliers
g. show picture
h. I think the distribution is slightly skewed right.
We want to see if we can predict the cost of a round-trip airfare based on the number of miles between cities. The
table below gives the round trip airfare from Boston.
Use this information to answer the following questions:
nicolle show answer
A biology teacher wants to know how the students in her department feel about a certain course sequence. She takes a list of students in her department in which the students are numbered as they are listed in alphabetical order. She uses a random number generator to select 40 numbers and interviews the students that those numbers represent in the alphabetical listing. Identify the type of sampling used in this example.
What is SRS?
The chart below gives the responses to a survey of 32 adults regarding preferred type of fiction novels for casual reading.
Make a frequency and relative frequency table using this information. (You can combine both into one
table. Express percentages to two decimal places)
nicolle present answer!
10. An English instructor gave a final exam and found a mean score of 73 points and a standard deviation of 5.8 points.
Assume that a Normal model can be applied.
a. Draw and label the Normal model for the exam scores.
b. Which scores are in the top 2.5%.
c. About what percentage of scores are between 67.2 and 84.6
a. show picture!
b. The top 2.5% will be all scores greater than 84.6 points
c. 81.5%
11. Do beavers benefit beetles? Researchers laid out 23 circular plots, each 4 meters in diameter, in an area where beavers were cutting down cottonwood trees.
In each plot, they counted the number of stumps from trees cut by beavers and the number of clusters of beetle larvae.
Ecologists think that the new sprouts from stumps are more tender than other cottonwood growth, so that beetles prefer them.
If so, more stumps should produce more beetle larvae.
Here are the data:
a. Y-hat = -1.29 + 11.89x
b. 11.89 larvae/stump
c. As the number of stumps increase by 1, the number of larvae found will increase by 11.89
d. 70.05 larvae
e. -2.16 larvae
Identify the sampling method:
The school board decides that the teachers at different school levels will have a different opinion. This district has 30 elementary schools, 10 middle schools and 5 high schools. Therefore, they design the study so that they randomly select 6 elementary schools, 2 middle schools and 1 high school (20% of each type) and interview all of the teachers of those selected schools
What is stratified?
The table below gives the grades from Test 1 for a previous semester. Use this data to create a frequency
distribution and a histogram. Begin with a lower class limit of 45 and use a class width of 12:
nicolle show them
check answer
Find the group mean for the following:
Answer is 81.9
(Note that the midpoints are 51, 63, 75, 87, and 99)
12. A study of breakfast cereals, an analysis was done to see if carbohydrate (grams) content could predict calories (calories).
The following information was produced from an analysis in Excel.
show image!
a. y-hat = 86.70 + 1.38x
b. r = .271
c. No because the correlation is so weak. Evidently this is not a strong linear correlation