AP Stat CWC Final Review Flashcards

Categorical Data

• Collecting data on car colors in a school parking lot results in categorical data.

Frequency Tables

• A frequency table showing ice cream flavor preferences indicates that the statement "One-half of the students chose vanilla or chocolate" is unsupported.

Market Research

• A study on color design preferences reveals that men's choices for black designs were not greater than for blue designs.

Relative Frequencies

• A bar chart illustrates that 12th grade students had the least participation in community service.

Golf Scores

• The sum of the squared deviations from the mean score of a golfer is derived from the individual scores.

Boxplots

• Only one conclusion about the size and range of two data sets represented in boxplots can be drawn.

Normal Distribution Parameters

• An ATM's transaction count is normally distributed with a mean of 80 and a standard deviation of 10.

Processing Times

• The proportion of coffee shop orders processed in under 240 seconds is estimated at 0.17.

Proportion Estimation

• Sampling distribution normality cannot be assumed with only 30 residents, where 28 commute by subway.

Conditions for Inference

• Valid statistical inferences regarding a sample proportion require conditions related to sampling methods and sample sizes.

Confidence Intervals

• A 95% confidence interval suggests a proportion of a population thinking climate change is a problem lies between 0.146 and 0.214.

One-Sample Z-Test

• The correct test statistic for investigating differences in bat wingspans is calculated using specified population and sample proportions.

Statistical Errors

• To mitigate Type II errors in hypothesis testing, a significance level increase is advisable.

Interval Estimates

• A 98% confidence interval for blemished apples ranges approximately between -105 and 265.

Confidence Interval Interpretation

• A confidence interval for differences in proportions favors an increase in arts spending among a specific district's voters.

Expected Values

• In a study of animal types at a vet clinic, expected distributions based on historical percentages are calculated for 230 animals treated.

Chi-Square Test

• A sample chi-square test determines the appropriateness of auditing based on job levels, with interpretation centered on p-values.

Experimental Design

• Random assignment in a medical study supports independence, crucial for chi-square tests of homogeneity.

Chi-Square Test of Independence

• Investigating the relationship between age groups and cell phone brand preference uses a chi-square test of independence.

Linear Regression

• The equation for chirp count and temperature models an increase in temperature correlated with increased chirp frequency.

Least Squares Regression Line

• Regression statistics provide potential least squares regression line based on given means and standard deviations for variables.

Stratified Sampling

• Stratified random sampling is preferable when subgroups exhibit considerable similarity within strata.

Census Surveys

• Census data collected from all bank employees negates the need for inference procedures about volunteer participation.

Sampling Methods

• True simple random samples can be achieved by random number selection methods.

Sampling Procedure Concerns

• A sampling method may overlook underrepresented groups such as registered voters with unlisted numbers.

Minimizing Response Bias

• Response bias can be minimized through meticulous question design and pre-testing.

Confounding Variables

• An experiment on rubber band elasticity risks confounding effects between temperature and brand.

Experimental Design

• A coin-flip method for detergent testing exemplifies a completely randomized design for effectiveness comparison.

Cause-and-Effect Relationships

• Controlled experiments are necessary for establishing cause-and-effect links between variables.

Medical Study Caution

• Results from a physician study caution against blanket recommendations, owing to gender and occupation limitations.

Confidence Interval Calculation

• A repair cost sample leads to a specific confidence interval around the average cost based on calculated mean and deviation.

Independence Among Observations

• A finite population must be significantly larger than the sample size to ensure negligible observational dependence.

Null Hypothesis Testing

• A low p-value indicates rejection of the null hypothesis in favor of indicating that mean differences exist.

Alternative Hypothesis

• Concerns about perchlorate levels in drinking water establish a test for mean values exceeding safety thresholds.

Sample Mean Analysis

• A mean comparison test yields indications of significant difference in active ingredient content across sampled tablets.

Independent T-Test

• A one-sided two-sample t-test is suitable for assessing whether Brand A batteries outlast Brand B based on life duration trials.

Difference Distribution

• Rolling two dice and computing their outcome differences results in a normal distribution appearance in graphical representation.

Microwave Oven Durability

• The probability analysis surrounding microwave failure rates highlights potential concerns with both damage and operational lifetime.### Microwave Oven Delivery
• Probability of a damaged microwave oven failing in less than 2 years is 0.40.

Electronic Device Components

• Components A, B, and C have failure probabilities of 0.01, 0.03, and 0.04, respectively.
• Independent failures lead to a device failure probability of 0.922 in one year.

XYZ Office Supplies Company

• Expected profit for next year from calculators is $220,700.
• Profit from wholesale calculators is $20 each; retail is $30 each.

Raffle Fundraising

• 1,000 raffle tickets sold for $1 each with a $50 prize.
• Expected net gain for ticket holders is -$0.95, indicating an average loss per ticket.

Concrete Delivery Profit

• Probability distribution for cubic yards of concrete sold results in an expected value of 19.25.
• Profit equation is Y = 75X - 100; standard deviation of profit Y is $432.00.

Rowboat Weight Limit

• Normal distribution of adult male weights: mean = 190 lbs, standard deviation = 10 lbs.
• Probability of a group of four exceeding the 800 lb weight limit is 0.023.

Sample Statistics and Constants

• Multiplying each value in a data set by a constant greater than 1 affects the mean, median, and standard deviation.

Prize Winning Probability

• To maximize the probability of winning a prize, choose n = 10 games.

Acceptable Chips in Circuit Boards

• Out of 4 randomly selected computer chips, the least probable number of acceptable chips (X) is 0.

Normality in Sampling Distribution

• Sales prices of homes were right-skewed; sample means from random samples of size 100 will yield an approximately normal distribution with a mean of $206,274 and standard deviation of $3,788.

Properties of Normal Random Variables

• Probability of a continuous random variable equating to a specific value (e.g., P(N=8)) is 0.

Confidence Interval on Regression

• For a sample of 12 students, the margin of error is calculated as (2.228)(0.745).

Conditions for Residual Plots

• Conditions checked in residual plots include linear relationship and constant standard deviation of y; confirmed by II only.

Evidence for Regression Model Fit

• A residual plot with a random scatter and no patterns indicates a strong evidence for the appropriateness of the regression line.

Confidence Interval Width and Sample Size

• Increasing sample size to 30 decreases the width of the confidence interval; claim made by Quincy is correct.

Agronomist's Hypothesis Testing

• Testing for a linear relationship between wheat stalk height and yield yielded a p-value of 0.25; null hypothesis is not rejected, showing insufficient evidence for a relationship.