Stat final study guide

The probability that a person will make 0,1,2, or 3 errors on his or her income tax return is 0.50, 0.30, 0.15, and 0.05, respectively. if 30 claims are selected, find the probability that 15 contain 0 errors, 8 will contain 1 error, 5 will contian 2 errors, and 2 will contain 3 errors

(n!/x!x2!x3!)* p1^x1*p2^x2

Computer Help Hot line recieves, on average, 6 calls per hour asking for assistance. For any randomly selected hour, find the probability that the company will recieve a) at least 6 calls b)4 or more calls c)at most 5 calls

*mean/average probability in a given time=poisson a) 1-Poisson(6,5)= b)1-poisson (6,3)= C)poission(6,5)

It has been reported that 20.4% of incoming freshmen indicate that they will major in business or a related field. A random sample of 400 incoming college freshmen was asked their preference, and 95 replied that they were considering business as a major. Estimate the true proportion of freshmen business majors with 98% confidence. does your interval contain 20.4?

1 prop z interval 0.188<p<0.287 za/2= last number of 98 confidence

The average movie admission price for a recent year was $7.18. The population variance was 3.81. A random Sample of 15 theater admission price has a means of $8.02 with standard deviation of $2.08. at a=0.05, is there sufficient evidence to conclude a difference from the population variance? Assume the variable is normally distributed

Chi square x2= (n-1)s^2/ O^2 O=variance o2=s.d

Of the total population of the United State, 20% live in the northeast. if 200 residents of the U.S are selected at random, find the probability that at least 50 live in the northeast

Graph first normalcdf ( 49.5, e99, 40.5,5.657) (lower, upper, mean, s.d) mean=n*p s.d= square root of npq

In addition to being grouped into four types, human blood is grouped by its rhesus(Rh) factor. Consider the figure below which shows the distribution of these groups for americans RH+ 37% 34% 10% 4% RH- 6% 6% 2% 1% O A B AB Find the prob that the person a) has o negative blood b) Has type O blood given the person is Rh+ c) has a+ or AB=blood d) Has Rh- given that the person has type B

P (AIB) p(And B)/ P (B)

Two dice are rolled. Find the probability of getting a) sum of 8,9,10 d) doubles or sum of 7 c) a sum greater than 9 or less than 4

Sample Space

The number of grams of protein in a random selection of granola and protein bars are listed below. 14 15 11 4 26 10 24 15 12 15 10 27 8 10 a) Find the percentile rank of 11 in the data set. b) What value corresponds to the 60th percentile? c)Determine the quartiles. d)Graph the box and whisker plot. e)find the lower and upper fences. f)Are there any outliers? Explain

a) Percentile rank= (# of values below X +.5)/(total # of values) b) (total # of values *percentile)/(100) c) Q3=median. Q1=median of upper half Q2=mean of lower half d) add the quartiles, upperfences and highest/lowest values. Box is around the quartiles e) LF= Q1-(1.5*IQR) UF=Q3+(1.5*IQR) IQR=Q3-Q1 f)Outliers are above or below the fences

IF 60% of all women are employed outside the home, find the probability that in a sample of 20 women, a) exactly 15 are employed b) at least 10 are employed c) at most 5 are not employed outside the home d) find the mean variance and s.d of the women

binomial is only 2 outsomes and includes percentage poisson no percentage binomial pds 1-binomialcdf binomialcdf 4.5

The American heart association reccommends a daily cholesterol intake of less than 300 mg. Here are the cholesterol amounts in a random sample of single servings of grilled meats. Estimate the standard deviation in cholesterol with 95% confidence. Assume the variable is normally distrubuted. 90 200 80 105 95 85 70 105 115 110 100 225 125 130 145

confidence=interval chi square (n-1)s^2 / X2R <o2< (n-1)s^2 /X2 l s=calc sx

The number of students who belong to the dance company at each of several randomly selected small universities is shown here. Estimate the true population means size of a university dance company with 99% confidence 21 25 32 22 28 30 29 30 47 26 35 26 35 26 28 28 32 27 40

confidence=interval n=19 means t interval <u<

The distrubution of the number of errots that 10 students made on a typing test is error= 0-2, 3-5, 6-8, 9-11, 12-14 Frequency = 1, 3, 4, 1, 1, ?= ?= ?= Find a) mean b)mode c) modal class d)variance e) standard deviation

find xm, xmf xm2f mode=7 variance= n* xm2f- (xmf)^2 /(n) (n-1) s.d = square root

An Automobile dealer find that the average price of a previously owned vehicle is $8256. He decides to sell cars that will appeal to the middle 60% of the market in terms of price. ind the maximum and minimum prices of the cars that the dealer will sell. The standard dev is $1150, and the variable is normally distributed

graph lowe= invmorn(.2... upper= invnorm 1-.2

A Box contains 3 $1 bills, two $5 bills and one $20 bill. Constuct a probability distribution for the data if x represents the value of a single bill drawn at random and then replaced. find the mean, variance, and standard deviation

grph x and p(x) mean subpx and x variance=( sub x^2and px )- mean s.d = square root

A researcher wishes to be 95% confidence that her estimate of the true proportion of individuals who travel oversears is within 4% of true proportion. Find the sample necessary if, in a prior study, a sample of 200 people showed that 40 traveled overseas last year

n=pq (zae/e)^2

Women comprise 80.3% of all elementary school teachers. in a random sample of 300 elemtary teacher,s what is the probability that less than 3/4 are women

normalcdf(lower, upper, mean,sd) mean =np s.d=npq swuare root 49.5

About 30% of all burglaries are through an open or unlocked door or window. A random sample of 130 burglaries indicated that 85 were not via an open or unlocked door or window. At the a=0.05 level of significance, can it be concluded that this differs from the stated proportions

proportion, z level 1. reject, there is enough e *find the number open p^ = x/n graph

The Average monthly cell phone bill was reported to be $50.07 by the U.S. wireless industry. Random sampling of a large cell phone company found the following monthly cell phone charge in dollars 55.83 49.88 62.98 70.42 60.47 52.45 49.20 50.02 58.60 51.29 at a=0.05 level of significance, can it be concluded that the average phone bill has increased?

t distribution

A random sample of the number of farms in various states follows. Estimate the mean number of farms per state with 90% confidence 47 95 54 33 64 4 8 57 9 80 8 90 3 49 4 44 79 80 48 16 68 7 15 21 52 6 78 109 40 50 29

z interval find s 34.4<u<52.688

A motorist claims that the south boro police issue an average of 60 speeding ticket per day. These data below show the number of speeding tickets issued each day for a randomly selected period of 30days. Is there enough evidence to reject the motorist claim at a=0.05

z test Claim =first one two tailes 1. do not reject the null hypothesis There is enough evidence to reject the motorist's claim.