Bias and Sampling
Probability
Shape center and spread
TI-Nspire Tricks
100
This type of bias occurs when some groups in the population are less likely to be included in the sample.
What is undercoverage bias?
100
A company is randomly selecting two employees to attend a special training seminar. There are five junior employees and four senior employees eligible. This is the probability that both are junior employees or both senior employees.
What is 4/9?
5/9 * 4/8 + 4/9 * 3/8 = 4/9
100
The following graph shows the distribution of the probabilities in a set of data, and has this type of distribution.
What is a uniform distribution?
100
This calculator function is used for the following question: “What is the probability that he does not sell a game console until the 8th customer?”
What is GeometricPdf?
(Gives the probability that the first success (a sale) happens on the 8th customer, after 7 failures.)
200
While aiming to collect data from every individual in the population, this type of study is often costly, time-consuming, and still susceptible to certain types of non-sampling error.
What is a Census?
200
A gambler has flipped a casino chip and it landed on “heads” 10 times consecutively. This is the probability that the next flip will also result in heads.
What is 50%?
200
A random sample of books in a library was collected, and the age of the books was recorded. The boxplot has this value for its IQR.
What is 16?
Q1 - Q3 = 19 - 3 = 16
200
This calculator function is used for the following question: “What is the probability that exactly 2 of the first 10 customers buy game consoles?”
What is BinomPdf?
(To find the probability of getting exactly X successes in a binomial setting.)
300
A researcher is studying the prevalence of a rare disease in a large and diverse population. To ensure that individuals with and without the condition are adequately represented in their study sample, they first identify all known individuals with the condition, and then, separately, they take a random sample of individuals from the rest of the population who do not have the condition. They then combine these two groups for their analysis.
What is Stratified sampling?
300
A bottled water company reports that 99.5% of its bottles are sealed properly. On average, this is the number of bottles you would expect to inspect before finding one that is not sealed correctly.
What is 200?
1/0.005 = 200
300
The parallel box plots shown below summarize the data sets for the number of points team A and team B score during their basketball games in one season. This team has a larger range.
What is Team A?
300
This calculator function is used for the following question: “What is the probability that at least 5 of his first 50 customers buy game consoles?”
What is BinomCdf?
(To find the probability of getting at most X successes in a binomial setting.)
400
A researcher wants to quickly gather opinions on a new product. They stand outside a popular shopping mall and ask people who walk by if they are willing to take a short survey.
What is Convenience sampling?
400
In a 2025 consumer study, it was reported that 50.5% of vacation cabins had internet access. If four cabins are chosen at random, this is the probability that all four have internet access.
What is 6.50%?
P(internet)=0.505
P(all 4 internet)=0.505^4 = 0.0650377506 = 6.50%
400
A college student conducts a study of cats in different environments. The student records the weight in pounds for each cat in a sample of 100 cats. After the measurements were taken, the scale used was found to be defective. To fix the issue, the student adjusted the measurements by subtracting 5 pounds from each measurement. This summary statistic has the same value before and after the adjustment.
What is the IQR?
400
This calculator function is used for the following question: “It is generally believed that right handedness affects about 65% of children. A school district gives tests to 133 incoming kindergarten children .What is the probability that in this group over 65% of the children will be found to be right-handed?”
What is BinomCdf?
(To find the probability of getting at most X successes in a binomial setting.)
500
UNIQLO, a fashion brand, sends out an email survey to all customers who made a purchase in the last month, asking them to rate their satisfaction with their recent shopping experience. Only 5% of the customers who received the email completed the survey.
What is Non-response bias?
500
In a 2025 survey of campsite amenities, it was found that 56.5% of campsites had access to electricity. If three campsites are selected at random, this is the probability that at least one of them had electricity.
What is 91.78%?
P(none)=0.0822
P(at least one) = 1−0.0822 = 0.9178 = 91.78%
500
A graph of the number of fruits sold at a certain store each day for the month of July shows that the distribution is skewed to the left. This measure of center is less than the median.
What is the mean?
500
This calculator function is used for the following question: “What test score corresponds to the top 10% of students if the scores are normally distributed with a mean of 75 and a standard deviation of 8?”
What is Invnorm?
(To find a boundary value in a normal distribution.)