algebra 2b - unit 6: exam

which answers describe a data set that is not a normal distribution? select all that apply.

a data set that is asymmetrical a data set that has a mean of 15 and a median of 9 a data set where 50% of the data are more than 1 standard deviation from the mean

a scientist compares the body lengths between three samples of species of salmon: chum salmon, pink salmon, and atlantic salmon. to do this, he collects six fish of each species and measures their lengths. the body lengths from the three samples of salmon are below, in cm: based on this data, which of the following are true? select all that apply.

atlantic salmon have the highest length, on average. chum salmon are the shortest in length, on average. the average length of pink salmon is between chum salmon and atlantic salmon.

what is the likelihood of the result, like the one the biologist observed in the study, occurring by chance?

1%

a researcher is interested in understanding the annual salaries and gender of software engineers in california. she collects a random sample of software engineers from california and obtains the following data: based on the data, what are the best estimates of gender and income in the population? select all that apply.

43% of software engineers in california are women. the average software engineer in california earns $97,200 per year.

all of the students in mr. clarke's class took a benchmark test. when mr. clarke analyzed the students' grades, he found that they were normally distributed and that __[blank]__ of the students received grades with z-scores between −0.75 and 1.15

64.83%

in a particular soccer league, the mean height of the players is 67 inches with a standard deviation of 3 inches. the heights are normally distributed, so 95.4% of the heights fall into a certain range of values around the mean. select the height(s) that fall(s) into this range of values. select all that apply.

72 70 62

amanda scored 87% on a math test. the following curve shows the results of her whole class. about what percentage of students did amanda score higher than?

77.34%

what is the probability that a randomly chosen observation falls within the shaded region?

95%

a university conducts a study of tobacco use among 1,000 of its students. the school surveys male and female volunteers to find the frequency of tobacco use. the study finds that, of the people surveyed, 250 men and 50 women regularly use tobacco. the university concludes that male students use tobacco more frequently than female students. which of the following situations would create a confounding variable (lurking variable) that could impact the study?

if the university surveyed more men than women, the number of male and female participants would be a confounding variable. if the men who took the survey all used tobacco at least once in high school, the participant history could be a confounding variable.

muriel is conducting research for a study about the work habits of employees in an office. she collects data by interviewing employees out of a total of 40 employees that work in the office. what sampling method would provide her the most representative sample?

muriel writes down the names of all 40 employees on individual pieces of paper. she then folds the pieces of paper up, places them in a bowl, and shakes the bowl around to mix up the pieces of paper. she then draws 10 pieces of paper out of the bowl and interviews the employees that have their names on those tickets.

julie is an education researcher interested in understanding the effects of tutoring on student performance. there are many ways she could study this question. match each research method with a description of how julie could conduct this study.

observational study : without interacting with any students, julie randomly selects 20 students from a tutoring program and 20 students not a tutoring program. she then looks up their grades in the student records. experiment : julie randomly assigns a sample of students to receive tutoring assistance or a control condition where they do not receive tutoring. she then examines changes in student grades at the beginning of the study vs. three months later survey : julie sends out a questionnaire to ask students whether they have used a tutor. the questionnaire also asks students to rate how they are doing in school on a scale from 1 (not very well) to 10 (very well)

based on this information, raymond predicts that he will be more likely to draw a spades suit from a deck of cards rather than a club suit. what is wrong with this prediction?

raymond ran a low number of simulations. therefore, the predictions of the simulation could vary considerably from the actual results.

an economist wishes to model potential outcomes in the stock market in the upcoming year. to do this, she decides to conduct a simulation study. what would be the best way to go about doing this?

the economist conducts a model with 10,000 simulations of the stock market, basing her simulations on stock market data from the past 5 years.

a camera manufacturer sends out 90 camera shipments each week, and each shipment contains 1,000 cameras. an inspector inspects 2 of the shipments before they are sent. after the inspections, the inspector concludes with 98% confidence that 0.9% of each shipment will be defective, with a margin of error of 0.5%. what conclusion can you draw from the size of the margin of error in this inspection?

the margin of error in this inspection is relatively low. this means that for 98% of all shipments, the statistic calculated by the inspector, 0.9%, is very similar to the true parameter.

a political campaign researcher sends a survey out to 100 randomly selected voters in massachusetts. the survey asks the voters how they plan to vote on a proposal to raise taxes on casinos. the voters respond to one of the three options: voting for the proposal, voting against the proposal, or if they are undecided. the researcher finds that 54% of the voters plan to vote for the proposal, 40% plan to vote against the proposal, and 6% are undecided. what option is most likely the purpose of this study?

the researcher wants to get an estimate of how many voters in massachusetts will vote for and against the proposal.

what is the correct conclusion that the botanist should make?

the results are not statistically significant. they do not suggest that the pH level of the soil had any effect on foxglove plant growth.

a botanist wants to examine the effects of a chemical on plant growth, so he runs an experiment. he gives the chemical to one species of plant on the left side of his greenhouse. the other species of plant on the right side of the greenhouse is assigned to the control group and does not receive the chemical. the botanist discovers that the plants that received the chemical grew more, on average, than those that did not receive the chemical. he concludes that the chemical is effective for promoting plant growth. what are the problems with this experiment and the reasoning of the botanist?

the side of the greenhouse the plants are on and the plant species are confounding variables. it is difficult for the botanist to rule out other explanations for the results that do not involve the chemical. the botanist failed to randomly assign the plants to each condition. this makes it difficult to know if the chemical actually caused plants to grow.