3.1
Is this an example of a parameter or statistic:
The average GPA of all graduating seniors at a midwestern university. Determine whether this describes a parameter or a statistic, and select the correct notation.
parameter
Bonus: what is the notation?
How do we calculate an interval estimates when provided the margin of error?
statistic (+ and -) margin of error
Bonus: What is the equation for 95% confidence intervals?
Using the worksheet: P1 EX2
If we select one candy at random, what is the probability that it is not blue?
0.750
Using worksheet: EX 2.6
Identify the explanatory variable and the response variable in this study.
Distance --> Trip Cost
Using the worksheet: EX 2.5
Does the association appear mostly negative or mostly postive?
mostly negative (strong negative)
True or False:
Standard error goes up directly with sample size.
False
Use the information to construct a 95% confidence interval and give notation of the parameter being estimated:
a) A sample survey finds a statistic of "p hat" = 0.65 with a standard error of 0.03.
b) The difference in two sample proportions is ("p hat" 1 - "p hat" 2 = 0.8), with a margin of error of 0.03
a) P(population proportion) = 0.59 to 0.71
b) P1 - P2 = 0.05 to 0.11
Using the worksheet: P1 EX 2
If we select one candy, keep it, and then select a second one, what is the probability that the first one is red and the second one is green?
0.030
Using the worksheet: EX 2.6
Use the regression line equation to predict the total cost of a ride-share trip that goes a distance of 8 miles.
$23.10
Using the worksheet: EX 2.5
Which correlation best matches the scatterplot? Choose only one.
-0.925, -0.150, 0.051, 0.895
-0.925
Using statkey: Baseball Player-4e (2024 salary in millions)
n = 10
generate 1000 sample proportions
How likely are we to see results that match each of the following sample proportions?
0.5 , 4.15, 11
0.5 = iii
4.15 = i
11 = ii
A random sample of n = 520 students at a large university found that the average number of hours spent exercising per week is 6.4 hours, with a margin of error of 1.8 hours.
Calculate an interval estimate for the average number of texts sent/received per day.
4.6 to 8.2
Bonus: What is the correct notation for the statistic?
Bonus x2: based on the interval would, "muh"=4.0 be a plausible value for the true population? explain
Using the worksheet: P1 EX1
If a student is Full-Time, what is the probability that they prefer a Hybrid format?
0.688
Using the worksheet: EX 2.6
An observed point at 8 miles was $36.36. Calculate the residual.
$13.26
Using the worksheet:
Can the results from this study be used to conclude, “There is a cause-and-effect relationship between a car's mileage and its price”?
No. This was an observational study
What does one single dot in this scenario represent? Include the correct notation:
A sampling distribution for the proportion of employed adults in a state who work entirely from remote positions, based on random samples of size n = 400.
each dot is a sample of 400 employed adults
and a sample proportion "p hat"
An October 2026 survey of a random sample of n = 1,150 fully remote employees found that 42% consider "work-life boundary blurring" to be their top professional challenge. The margin of error for the estimate is 0.03
Write a formal interpretation for the interval estimate in the context of the situation.
We are 95% confident that the true proportion of all fully remote employees who consider work-life boundary blurring to be their top professional challenge is between 39% and 45%.
Bonus: what is the correct notation and value for the statistic?
Using the work sheet: P1 EX 1
What is the probability that a student chosen at random is Unemployed and prefers an In-Person format?
0.120
Using Worksheet: EX 2.6
Interpret the value of the slope in the context of this study.
For each additional mile a passenger travels, the total trip cost is predicted to increase by $2.20.
Using the Worksheet: EX 2.6
Interpret what the direction implies about mileage and price for these vehicles.
the more the milage increases, the more vehicles cost tend to decrease
Give the notation for the parameter and define the parameter within the context of the study’s purpose:
A survey of a random sample of 1,500 adults in a major city found that 450 of them reported wearing a smartwatch every day to track their health metrics.
P = the proportion of all adults in major city who wear a smartwatch everyday to track their health metrics.
Bonus: Give notation and calculate the value for the statistic that gives best estimate.
A study based on a random sample of 2,000 corporate employees asked whether they prefer a hybrid work schedule over a fully on-site schedule. Out of 900 tech industry employees, 540 preferred hybrid. Out of 1,100 finance industry employees, 550 preferred hybrid.
Interpret the 95% confidence interval in the context of the study.
We are 95% confident that the true difference in the proportion of all tech and finance employees who prefer a hybrid schedule is between 5.6% and 14.4% (with a higher proportion among tech employees).
Bonus: What is the difference of the sample proportions? Include notation
Using the worksheet: P1 EX 1
What is the probability that a student chosen at random is either Full-Time or prefers an Online format?
0.560
Using Worksheet: EX 2.6
Interpret the value of the intercept in the context of this new study.
If we have a trip with a distance of 0 miles, the cost might be $5.50.
Using the worksheet: EX 2.5
Describe cases represented in the general corner of the scatterplot.
Bottom-right: _________________________
Top-left:_____________________________
Top-Left: low milage, high costs