chap 3 and 4 statistic test
The square of the standard deviation is called the ______
variance
Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 8181 people in the 18-21 age bracket and finds that 42 of them respond and 39 refuse to respond. When 270 people in the 22-29 age bracket are contacted, 225 respond and 45 refuse to respond. Suppose that one of the 351 people is randomly selected. Find the probability of getting someone in the 22 dash 22-29 age bracket or someone who refused to respond
P(person is in the 22-29 age bracket or refused to respond=0.88
Use the following cell phone airport data speeds (Mbps) from a particular network. Find Upper Q 1Q1. 0.1 0.1 0.2 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 0.9 0.9 0.9 1.1 1.3 1.4 1.6 1.7 1.8 1.8 2.2 2.3 2.3 2.4 2.7 2.9 3.2 3.8 4.8 4.9 5.3 5.3 5.9 7.5 7.7 8.1 8.5 9.4 11.4 11.7 12.4 12.5 13.1 14.7 15.4 15.8 27.3
Q1=0.7 Mbps
The tallest living man at one time had a height of 239 cm. The shortest living man at that time had a height of 123.7 cm. Heights of men at that time had a mean of 171.38 cm and a standard deviation of 6.39 cm. Which of these two men had the height that was more extreme?
Since the z score for the tallest man is z=10.58 and the z score for the shortest man is z=−7.46, the tallest man had the height that was more extreme.
The tallest living man at one time had a height of 253 cm. The shortest living man at that time had a height of 72.1 cm. Heights of men at that time had a mean of 175.15 cm and a standard deviation of 7.33 cm. Which of these two men had the height that was more extreme?
Since the z score for the tallest man is z=10.62 and the z score for the shortest man is z=−14.06, the shortest man had the height that was more extreme.
Among 400 randomly selected drivers in the 16−18 age bracket, 219 were in a car crash in the last year. If a driver in that age bracket is randomly selected, what is the approximate probability that he or she will be in a car crash during the next year? Is it unlikely for a driver in that age bracket to be involved in a car crash during a year? Is the resulting value high enough to be of concern to those in the 16−18 age bracket? Consider an event to be "unlikely" if its probability is less than or equal to 0.05.
The probability that a randomly selected person in the 16−18 age bracket will be in a car crash this year is approximately 0.548 no yes
Use the data in the following table, which lists drive-thru order accuracy at popular fast food chains. Assume that orders are randomly selected from those included in the table. Drive-thru Restaurant A B C D Order Accurate 334 260 246 145 Order Not Accurate 38 52 40 11
The probability of getting an order that is not accurate is 0.125
Events that are _ cannot occur at the same time
disjoint
Two events A and B are _______ if the occurrence of one does not affect the probability of the occurrence of the other.
independent
A value at the center or middle of a data set is a(n)
measure of center
Which of the following values cannot be probabilities? 0.07, negative -0.49, square2, 5/3, 1, 3/5, 0, 1.22
square 2 1.22 5/3 -0.49
In a test of a gender-selection technique, results consisted of 252 baby girls and 8 baby boys. Based on this result, what is the probability of a girl born to a couple using this technique? Does it appear that the technique is effective in increasing the likelihood that a baby will be a girl?
The probability that a girl will be born using this technique is approximately 0.969 Does the technique appear effective in improving the likelihood of having a girl baby? Yes
Which measure of variation is most sensitive to extreme values?
Range
It is impossibleIt is impossible to get 6 jacks when selecting6 jacks when selecting cards from a shuffled deck. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive.
0
Four of the 100 digital video recorders (DVRs) in an inventory are known to be defective. What is the probability that a randomly selected item is defective?
0.04
A research center poll showed that 79% of people believe that it is morally wrong to not report all income on tax returns. What is the probability that someone does not have this belief?
0.21
In a test of a gender-selection technique, results consisted of 248 baby girls and 13 baby boys. Based on this result, what is the probability of a girl born to a couple using this technique? Does it appear that the technique is effective in increasing the likelihood that a baby will be a girl?
0.950 yes
You are certain to get 3 jacks when selecting 51 cards from a shuffled deck. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive.
1
Assume that a company hires employees on the different business days of the month left parenthesis Assumethe different business days of the month (Assume 20 business days in a month right parenthesis nbsp20 business days in a month) with equal likelihood. Complete parts (a) through (c) below.
1/400 1/20 1/8000
To the right are the outcomes that are possible when a couple has three children. Assume that boys and girls are equally likely, so that the eight simple events are equally likely. Find the probability that when a couple has three children, there are exactly 0 girls.
1/8
The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 256.2 and a standard deviation of 63.7 (All units are 1000 cells/muμL.) Using the empirical rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 11 standard deviation of the mean, or between 192.5 and 319.9? b. What is the approximate percentage of women with platelet counts between 128.8 and 383.6?
A. 68 B. 95
When using the ____always be careful to avoid double-counting outcomes
Addition Rule
When a man observed a sobriety checkpoint conducted by a police department, he saw 695695 drivers were screened and 99 were arrested for driving while intoxicated. Based on those results, we can estimate that Upper P left parenthesis Upper W right parenthesisP(W)equals=0.012950.01295, where W denotes the event of screening a driver and getting someone who is intoxicated. What does Upper P left parenthesis Upper W overbar right parenthesisPW denote, and what is its value?
P(W) denotes the probability of screening a driver and finding that he or she is not intoxicated. P(W)= 0.98705
Pollsters are concerned about declining levels of cooperation among persons contacted in surveys. A pollster contacts 87 people in the 18-21 age bracket and finds that 69of them respond and 18 refuse to respond. When 263 people in the 22-29 age bracket are contacted, 218 respond and 45 refuse to respond. Suppose that one of the 350 people is randomly selected. Find the probability of getting someone in the18-21 age bracket or someone who refused to respond.
P(person is in the 18-21 age bracket or refused to respond= 0.377
Use the following cell phone airport data speeds (Mbps) from a particular network. Find Upper P 60P60. 0.10.1 0.10.1 0.20.2 0.20.2 0.30.3 0.30.3 0.40.4 0.40.4 0.50.5 0.60.6 0.60.6 0.60.6 0.80.8 0.80.8 0.80.8 0.90.9 1.21.2 1.31.3 1.31.3 1.41.4 1.51.5 1.61.6 2.22.2 2.42.4 2.42.4 2.82.8 2.92.9 3.33.3 3.43.4 4.44.4 4.64.6 4.94.9 5.25.2 6.56.5 7.97.9 9.49.4 10.110.1 11.211.2 11.811.8 12.112.1 12.212.2 12.712.7 13.213.2 13.313.3 13.513.5 13.813.8 14.914.9 15.415.4 15.615.6 28.228.2
P60=4.5Mbps 4.5 4.4 4.48 4.6
Determine whether the two events are disjoint for a single trial. (Hint: Consider "disjoint" to be equivalent to "separate" or "not overlapping.") Randomly selecting someone who plays hockeyhockey. Randomly selecting someone taking a biologybiology course.
The events are not disjoint. they can occur at the same time.
Listed below are the measured radiation emissions (in W/kg) corresponding to cell phones: A, B, C, D, E, F, G, H, I, J, and K respectively. The media often present reports about the dangers of cell phone radiation as a cause of cancer. Cell phone radiation must be 1.6 W/kg or less. Find the a. mean, b. median, c. midrange, and d. mode for the data. Also complete part e. 0.22 0.86 0.41 1.28 0.69 0.92 0.54 0.72 0.55 0.83 0.53
The midrange is 0.75 The median is 0.69 The mean is 0.686 no mode The maximum data value is the most relevant statistic, because it is closest to the limit of 1.6W/kg and that cell phone should be avoided.
FiveFive of the 100 digital video recorders (DVRs) in an inventory are known to be defective. What is the probability that a randomly selected item is defective?
The probability is 0.05
Assume that a company hires employees on Mondays comma Tuesdays comma or WednesdaysMondays, Tuesdays, or Wednesdays nothingwith equal likelihood. Complete parts (a) through (c) below.
The probability is 1/9 b. If two different employees are randomly selected, what is the probability that they were both hired on the same day of the weekday of the week? The probability is one third 1/3. c. What is the probability that 66 people in the same department were all hired on the same day of the weekday of the week? Is such an event unlikely? The probability is StartFraction 1 Over 243 EndFraction 1/243. Is such an event unlikely? Yes, because the probability that all 6 people were hired on the same day of the week is less than or equal to 0.05
Refer to the sample data for pre-employment drug screening shown below. If one of the subjects is randomly selected, what is the probability that the test result is a false positive? Who would suffer from a false positive result? Why? Pre-Employment Drug Screening Results Positive test result Negative test result Drug Use Is Indicated Drug Use Is Not Indicated Subject Uses Drugs 43 8 Subject Is Not a Drug User 1 28
The probability of a false positive test result is 0.013 The person tested would suffer because he or she would be suspected of using drugs when in reality he or she does not use drugs.
In a genetics experiment on peas, one sample of offspring contained 388 green peas and 126 yellow peas. Based on those results, estimate the probability of getting an offspring pea that is green. Is the result reasonably close to the value of three fourths 3/4 that was expected?
The probability of getting a green pea is approximately 0.755 Yes
In a genetics experiment on peas, one sample of offspring contained 388 green peas and 37 yellow peas. Based on those results, estimate the probability of getting an offspring pea that is green. Is the result reasonably close to the value of three fourths 3/4 that was expected?
The probability of getting a green pea is approximately 0.913 Is this probability reasonably close to three fourths 3/4? Choose the correct answer below. NO it is not reasonably close
Among 400 randomly selected drivers in the 16−18 age bracket, 313 were in a car crash in the last year. If a driver in that age bracket is randomly selected, what is the approximate probability that he or she will be in a car crash during the next year? Is it unlikely for a driver in that age bracket to be involved in a car crash during a year? Is the resulting value high enough to be of concern to those in the 16−18 age bracket? Consider an event to be "unlikely" if its probability is less than or equal to 0.05.
The probability that a randomly selected person in the 16−18 age bracket will be in a car crash this year is approximately 0.783 Would it be unlikely for a driver in that age bracket to be involved in a car crash this year? NO Is the probability high enough to be of concern to those in the 16 minus 1816−18 age bracket? YES
A research center poll showed that 80% of people believe that it is morally wrong to not report all income on tax returns. What is the probability that someone does not have this belief?
The probability that someone does not believe that it is morally wrong to not report all income on tax returns is 0.20
Listed below are foot lengths in inches for 11 randomly selected people taken in 1988. Find the range, variance, and standard deviation for the given sample data. Include appropriate units in the results. Are the statistics representative of the current population of all people? 10.3 9 9.7 8.6 8.7 10.3 10.5 9.69.6 10.4 10.3 10.2
The range of the sample data is 1.9 inches. (Type an integer or a decimal. Do not round.) The standard deviation of the sample data is 0.71 inches. (Round to two decimal places as needed.) The variance of the sample data is 0.51 inches2. (Round to two decimal places as needed.) Since the measurements were made in 1988, it is necessarily representative of the population today.
Listed below are prices in dollars for one night at different hotels in a certain region. Find the range, variance, and standard deviation for the given sample data. Include appropriate units in the results. How useful are the measures of variation for someone searching for a room? 262 195 189 278 287 144 295 279
The range of the sample data is 151 dollars. The standard deviation of the sample data is 56.7 dollars. The variance of the sample data is 3216.4 dollars squared . The measures of variation are not very useful because when searching for a room, low prices, location, and good accommodations are more important than the amount of variation in the area
Find the (a) mean, (b) median, (c) mode, and (d) midrange for the data and then (e) answer the given question. Listed below are the weights in pounds of 1111 players randomly selected from the roster of a championship sports team. Are the results likely to be representative of all players in that sport's league? 208208 306306 233233 232232 254254 262262 253253 283283 232232 199199 253253
The results are not likely to be representative because the championship team may not be representative of the entire league.
Listed below are the measured radiation absorption rates (in W/kg) corresponding to 1111 cell phones. Use the given data to construct a boxplot and identify the 5-number summary. 1.47 0.96 0.77 0.52 0.51 1.02 0.79 0.83 1.43 0.53 1.32
The 5-number summary is 0.51, 0.53, 0.83, 1.32, and 1.47, all in W/kg.
The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 254.9 and a standard deviation of 68.5. (All units are 1000 cells/muμL.) Using the empirical rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 33 standard deviations of the mean, or between 49.4 and 460.4? b. What is the approximate percentage of women with platelet counts between 186.4 and 323.4?
a. Approximately 99.7% of women in this group have platelet counts within 33 standard deviations of the mean, or between 49.4 and 460.4 (Type an integer or a decimal. Do not round.) b. Approximately 68% of women in this group have platelet counts between 186.4 and 323.4. (Type an integer or a decimal. Do not round.)
Refer to the table below. Given that 2 of the 145145 subjects are randomly selected, complete parts (a) and (b). Group O A B AB Type Rh+ 60 37 15 8 Rh− 12 10 2 1
a. Assume that the selections are made with replacement. What is the probability that the 2 selected subjects are both group Upper BB and type Rh Superscript plusRh+? 0.0107Round to four decimal places as needed.) b. Assume the selections are made without replacement. What is the probability that the 2 selected subjects are both group Upper BB and type Rh Superscript plusRh+? 0.0101 (Round to four decimal places as needed.)
Which word is associated with multiplication when computing probabilities?
and
