STATS FINAL AHHHH
What does n mean (arch)
"and" essentially the % of both
probability of a girl
(0,1,2) not equally likely
z score formula
(x-mean)/standard deviation
in a certain school, 17 percent of the students are enrolled in a psychology course, 28 percent are enrolled in a foreign language course, and 32 percent are enrolled in either a psychology course or a forelen language or both. What is the probability that a student chosen at random from this school will be enrolled in both a foreign language course and psychology course?
.13
The sale bin in a clothing store contains an assortment of t-shirts in different sizes. There are 9 small, 7 medium, and 4 large shirts. Alan is looking for a large shirt. He starts grabbing shirts one at a time and checking the size: After he checks each shirt, he leaves it outside the bin. What is the probability that the first large shirt he finds is the third one he checks?
.140
a tropical storm is classified as major if it has sustained winds greater than 110 miles per hour. Based on data from the past two decades, a meteorologist estimated the following percentages about future storms. 20% of all tropical storms will originate in the Atlantic Ocean, of which 20% will be classified asiajor3 30% of all tropical storms will originate in the eastern Pacific Ocean, of which 15% will be classified as major. 50% of all tropical storms will originate in the western Pacific Ocean, of which 25% will be classified as major.
.170
For flights from a particular airport in January, there is a 30 percent chance of a flight being delayed because of icy weather. If a flight is delayed because of icy weather, there is a 10 percent chance the flight will also be delayed because of a mechanical problem. If a flight is not delayed because of icy weather, there is a 5 percent chance that it will be delayed because of a mechanical problem. If one flight is selected at random from the airport in January, what is the probability that the flight selected will have at least one ofthe two types of delays?
.335
Opinion-polling organizations contact their respondents by sampling random telephone numbers. Assume that interviewers can now reach about 71% of U.S. households; while the percentage of those contacted who agree to cooperate with the survey is 31%.; Each household, it can be safely assumed; is independent of the others. What is the probability of failing to contact a household or oft contacting the household but not getting them to agree to the interview?
.78
what to do when a problem says "greater than"
1- z score % (chart)
A friend of your plans to toss a fair coin 200 times You watch the first 20 tosses and are surprised that she got 15 heads. But then you get bored and leave. How many heads do you expect her to have when she has finished all 200 tosses?
105
Log(y hat)
10^y
The caffeine content 8 ounce.sons of a certain cola drink is approximately normally distributed with mean 33 millierams (mg). A randomly selected 8-ounce can containing 35 mg of caffeine is 1.2 standard deviations above the mean. Approximately what percent of 8-ounce cans of the cola have a caffeine content greater than 33 mgt
12%
At a certain store, the distribution of weights of cartons of large eges is approximately normal with mean 26 ounces (02). Based on the distribution, which of the following intervals will contain the greatest proportion of cartons of large eggs at the store?
22oz to 28 oz
The height of 3-year-old boys is approximately normally distributed. Duncan and Shane are 3-year-old boys.Duncan is 32.0 inches tal/hand is at the 32nd percentile of the distribution. Shane is 34.0 inches tall and is at the 62nd percentile of the distribution. Which of the following is closest to the mean of the height distribution?
32.79
probability of your child's sex
BB, BG, GB, GG equally likely
Which of the following statements about a least-squares regression analysis is true? I. A point with a large residual is an outlier. II. A point with high leverage has a j-value that is not consistent with the other y-values in the set. III. The removal of an influential point from a data set could change the value of the correlation coefficient.
III only
the probability that a randomly selected visitor to a certain website will be asked to participate in an online survey is 0.40. Avery claims that for the next 5 visitors to the site, 2 will be asked to participate in the survey. Is Avery interpreting the probability correctly?
No, bc .40 reps P in the long run over many visits
General Addition Rule
P(A U B) = P(A) + P(B) - P(An B)
General Multiplication Rule
P(A n B) = P(A) × P(BIA)
indipendent
P(A) = P(AlB)
Conditional Probability
P(AIB) = P(An B) / P(B)
A new restaurant is interested in determining the best time-temperature combination for roasting a five-pound cut of lamb. The times to be tested are 45 minutes, 60 minutes, and 90 minutes at temperatures of 350 degrees Fahrenheit and 425 degrees Fahrenheit for each time, with the exception of the 90 minute - 425 degree combination. That combination is being eliminated because it will overcook the lamb, which leaves five combinations remaining. From 10 identical cuts of lamb, 2 are randomly selected to roast using each of the time-temperature combinations in the same oven. The quality of the finished product is evaluated for each roast. Which of the following is true?
The two cuts that are being roasted for each time-temperature combination are an example of replication.
A regional transportation authority is interested in estimating the mean number of minutes working adults in the region spend commuting to work on a typical day. A random sample of working adults will be selected from each of three strata: urban, suburban, and rural. Selected individuals will be asked the number of minutes they spend commuting to work on a typical day. Why is stratification used in this situation?
To decrease the variability in estimates of the mean commuting time
At a local ice-cream store, 210 people were surveyed on whether they preferred eating ice cream from a cone or a cup. Of the 210 people surveyed, 70 were adults and 140 were children. Of the responses, 150 indicated the cone as the preferred method of eating ice cream. For those surveyed, there was no association between age and preferred method of eating ice cream. Which of the following tables shows the distribution of responses?
adult and cone: 50 adult and cup: 20
strong means that the value is
close to the LSRL
In a certain school district, students from grade 6 through grade 12 can participate in a school-sponsored community service activity. The following bar chart shows the relative frequencies of students from each grade who participate in the community service activity.
grade 12 had the least relative frequency
what is and isn't effected by the outlier
mean is effected median isn't
skewed r means
mean> med
A high school science teacher has 78 students. Of those students, 35 are in the band and 32 are on a sports team. There are 16 students who are not in the band or on a sports team. One student from the 78 students will be selected at random. Let event B represent the event of selecting a student in the band, and let event S represent the event of selecting a student on a sports team. Are B and S mutually exclusive events?
no, because P(B or S) = 5/78
In a large set of data that are approximately normally distributed, r is the value in the data set that has a z-score of -1.00 s is the value of the first quartile, and t is the value of the 20th percentile r s and t ranked from least to greatest
r, t, s
As part of a science experiment, a student recorded 10 measurements of the temperature of a liquid. One of the measurements was in outlier compared with the other 9 measurements. Which of the following must be true about the 9 measurements, excluding the Quilier, when compared with the 10 measurements? Note: An outlier is any number that is greater than the upper quartile or less than the lower quartile by at least 1.5 times the interquartile range.)
the SD of the 9 measurements is < the SD of the 10 measurements
A scatterplot of student heights, in inches, versus corresponding arm span length, in inches, is shown below. One of the points in The graph is labeled A.
the slope of the LSRL inc and correlation coefficient inc
A recent study examined 699 car accidents in Toronto over a fourteen-month period. Records of phone-service providers were used to determine whether the driver was using a cell phone during or immediately before the accident. Overall, the researchers found that drivers using cell phones were 4.3 times as likely to have an accident as drivers who were not using cell phones. The result was statistically significant. Which of the following can be concluded from this study?
there's a correlation between cell phone users and accidents, but not necessarily an association
A roadrunner is a desert bird that tends to run instead of fly. While running, the roadrunner uses its tail as a balance. A sample of roadrunners was taken, and the birds' total length, in centimeters (cm), and tail length, in cm, were recorded. The output shown in the table is from a least-squares regression to predict tail length given total length.
underestimate, bc the residual is pos
