Statistics Chapter 4 Review

Réussis tes devoirs et examens dès maintenant avec Quizwiz!

Twenty 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?

.20%

The principle of redundancy is used when system reliability is improved through redundant or backup components. Assume that a​ student's alarm clock has a 16.7​%

0.167 0.027890= 0.167 squared 0.004660= 0.167 cubed D. ​Yes, because total malfunction would not be​ impossible, but it would be unlikely.

A research center poll showed that 81​% 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

0.19

Eleven of the 50 digital video recorders​(DVRs) in an inventory are known to be defective. What is the probability that a randomly selected item is​defective?

0.22

Testing for a disease can be made more efficient by combining samples. If the samples from six people are combined and the mixture tests​ negative, then all six samples are negative. On the other​ hand, one positive sample will always test​ positive, no matter how many negative samples it is mixed with. Assuming the probability of a single sample testing positive is 0.05​,find the probability of a positive result for six samples combined into one mixture. Is the probability low enough so that further testing of the individual samples is rarely​ necessary?

0.265 The probability is not​ low, so further testing of the individual samples will frequently be a necessary event.

In a genetics experiment on​ peas, one sample of offspring contained 409 green peas and 504 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 34 that was​ expected?

0.448, no it is not close

The table below displays results from experiments with polygraph instruments. Find the positive predictive value for the test. That​ is, find the probability that the subject​ lied, given that the test yields a positive result.

0.683

For a certain casino slot machine, the odds in favor of a win are given as 83 to 17. Express the indicated degree of likelihood as a probability value between 0 and 1 inclusive.

0.83

In a test of a​ sex-selection technique, results consisted of 224 female babies and 14 male babies. Based on this​ result, what is the probability of a female being 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​ female?

0.941, yes

Assume that there is a 7​% rate of disk drive failure in a year. a. If all your computer data is stored on a hard disk drive with a copy stored on a second hard disk​ drive, what is the probability that during a​ year, you can avoid catastrophe with at least one working​ drive? b. If copies of all your computer data are stored on three independent hard disk​ drives, what is the probability that during a​ year, you can avoid catastrophe with at least one working​ drive?

0.9951= 1-0.0049 0.999657=1-0.000343

Winning the jackpot in a particular lottery requires that you select the correct four numbers between 1 and 59 ​and, in a separate​ drawing, you must also select the correct single number between 1 and 39. Find the probability of winning the jackpot.

1/17749914 4/59 3/58 2/57 1/56 1/39

On their first​ date, Kelly asks Mike to guess the date of her​ birth, not including the year. Complete parts a through c below.

1/365 ​Yes, it is unlikely for Mike to guess correctly on his first​ try, as the probability of a correct guess is very low. Already knew, very low

You want to obtain cash by using an​ ATM, but​ it's dark and you​ can't see your card when you insert it. The card must be inserted with the front side up and the printing configured so that the beginning of your name enters first. Complete parts​ (a) through​ (c)

1/4 3/16 This is a trick question. There is no finite number of​ attempts, because it is possible to get the wrong position every time.

A modified roulette wheel has 32 slots. One slot is​ 0, another is​ 00, and the others are numbered 1 through 30​, respectively. You are placing a bet that the outcome is an even number.​ (In roulette, 0 and 00 are neither odd nor​ even.)

15/32 17:15 17 19.27$

If radio station call letters must begin with either K or W and must include either two or three additional​ letters, how many different possibilities are​ there?

36504

Find the probability that when a couple has three ​children, at least one of them is a boy. ​(Assume that boys and girls are equally​ likely.)

7/8

In horse​ racing, a trifecta is a bet that the first three finishers in a race are​ selected, and they are selected in the correct order. Does a trifecta involve combinations or​ permutations? Explain.

Because the order of the first three finishers does make a​ difference, the trifecta involves permutations.

Let A be the event of rolling a die and getting​ 6, and let B be the event of tossing a coin and getting heads. When finding the probability that events A and B both​ occur, which formula​ applies?

P(A and B)= P(A)P(B)

Two different days of the week are randomly selected without replacement. Let W be the event of selecting Wednesday on the first​ selection, and let F be the event of selecting Friday on the second selection. When finding the probability that events W and F both​ occur, which formula​ applies?

P(A and B)=P(A)P(BIA)

In an​ experiment, college students were given either four quarters or a​ $1 bill and they could either keep the money or spend it on gum. The results are summarized in the table. Complete parts​ (a) through​ (c) below.

The probability is 0.675 0.3250. A student given four quarters is more likely to have spent the money. Your answer is correct.

A county clerk was supposed to use randomness to assign the order in which​ candidates' names appeared on voting ballots. Among 38 different​ ballots, Democratic candidate names were placed on the first line 35 times. The probability of a result that high is 0.000000033389. Assuming randomness was​ used, is the result of 35 Democratic candidate names being placed on the first line significantly​ low, significantly​ high, or​ neither?

The probability of a result of 35​, which is 0.000000033389​, is less than or equal to 0.05. The​ result, 3538​, is much higher than what is expected with randomness. The result of 35 is significantly high.

Order Accurate 332 278 237 149 Order Not Accurate 31 57 39 15 If one order is​ selected, find the probability of getting an order from Restaurant A or an order that is accurate. Are the events of selecting an order from Restaurant A and selecting an accurate order disjoint​ events?

The probability of getting an order from Restaurant A or an order that is accurate is 0.903 P The events are not disjoint because it is possible to receive an accurate order from Restaurant A.

If one order is​ selected, find the probability of getting an order that is not accurate or is from Restaurant C. Are the events of selecting an order that is not accurate and selecting an order from Restaurant C disjoint​ events?

The probability of getting an order from Restaurant C or an order that is not accurate is 0.3510 The events are not disjoint because it is possible to receive an inaccurate order from Restaurant C.

When randomly selecting​ adults, let M denote the event of randomly selecting a male and let B denote the event of randomly selecting someone with blue eyes. What does P(M|B) ​represent? Is P(M|B) the same as P(B|M)​?

The probability of getting a​ male, given that someone with blue eyes has been selected. ​No, because P(B|M) represents the probability of getting someone with blue​ eyes, given that a male has been selected.

Let event A=subject is telling the truth and event B=polygraph test indicates that the subject is lying. Use your own words to translate the notation P(B|A) into a verbal statement

The probability that the polygraph indicates lying given that the subject is actually telling the truth

In a particular survey of internet​ users, 3603 respondents say that they use social networking sites and 1457 respondents say that they do not use social networking sites. What is the probability that a randomly selected person uses a social networking​ site? Does that result suggest that it is likely​ (with a probability of 0.5 or​ greater) for someone to use social networking​ sites?

Yes​,because the probability of a respondent using social media is greater than 0.5.

Refer to the figure below in which surge protectors p and q are used to protect an expensive​ high-definition television. If there is a surge in the​ voltage, the surge protector reduces it to a safe level. Assume that each surge protector has a 0.97 probability of working correctly when a voltage surge occurs. Complete parts​ (a) through​ (c) below.

a. If the two surge protectors are arranged in​ series, what is the probability that a voltage surge will not damage the​ television? 0.99910 b. If the two surge protectors are arranged in​ parallel, what is the probability that a voltage surge will not damage the​ television? 0.9409 c. Which arrangement should be used for better​ protection? The series arrangement provides better protection because it has a higher probability of protection.

A modified roulette wheel has 44 slots. One slot is 0, another is 00, and the others are numbered 1 through 42 respectively. You are placing a bet that the outcome is an odd number. {In roulette, 0 and 00 are neither odd nor even}

a. the probability of einning is 21/44b. The actual odds against winning are....1-(21/44)= 23:21c. If you win, the payoff is $16d. 16×(23/21)= 17.52

When using the​ _______ always be careful to avoid​ double-counting outcomes.

addition rule

Each of two parents has the genotype red/brown​, which consists of the pair of alleles that determine hair color​, and each parent contributes one of those alleles to a child. Assume that if the child has at least one red ​allele, that color will dominate and the​ child's hair color will be red. a. List the different possible outcomes. Assume that these outcomes are equally likely. b. What is the probability that a child of these parents will have the brown/brown ​genotype? c. What is the probability that the child will have red hair color​?

red/red, red/brown, brown/red, and brown/brown 0.25 0.75

The​ _______ for a procedure consists of all possible simple events or all outcomes that cannot be broken down any further.

sample space

Let A denote the event of placing a ​$1 straight bet on a certain lottery and winning. Suppose​ that, for this particular​ lottery, there are 4,480 different ways that you can select the four digits​ (with repetition​ allowed) in this​ lottery, and only one of those​ four-digit numbers will be the winner. What is the value of​ P(A)? What is the value of ​P(A​)?

​P(A)=0.000220 What is the value of ​P(A​)? ​P(A​)=0.999780


Ensembles d'études connexes

Ch. 11 NCLEX Questions Foundations of Nursing

View Set

Computer Programming Chapter 1 + 2

View Set