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Suppose the average client charge per hour for out-of-court work by lawyers in the state of Iowa is $\$ 125 .$ Suppose further that a random telephone sample of 32 lawyers in Iowa is taken and that the sample average charge per hour for out-of-court work is $\$ 110 .$ If the population variance is $\$ 525$, what is the probability of getting a sample mean of $\$ 110$ or larger? What is the probability of getting a sample mean larger than $\$ 135$ per hour? What is the probability of getting a sample mean of between $\$ 120$ and $\$ 130$ per hour?

Suppose the average client charge per hour for out-of-court work by lawyers in the state of Iowa is $\$ 125 .$ Suppose further that a random telephone sample of 32 lawyers in Iowa is taken and that the sample average charge per hour for out-of-court work is $\$ 110 .$ If the population variance is $\$ 525$, what is the probability of getting a sample mean of $\$ 110$ or larger? What is the probability of getting a sample mean larger than $\$ 135$ per hour? What is the probability of getting a sample mean of between $\$ 120$ and $\$ 130$ per hour?

Business Statistics - For Contemporary Decision Making

Sampling and Sampling Distributions

Sampling Distribution of p

Consider the following hypothesis test. $$\begin{array}{l} H_{0}: \mu_{d} \leq 0 \\ H_{\mathrm{a}}: \mu_{d}>0 \end{array}$$ The following data are from matched samples taken from two populations. $$\begin{array}{ccc} & {\text { Population }} \\ \text { Element } & \mathbf{1} & \mathbf{2} \\ 1 & 21 & 20 \\ 2 & 28 & 26 \\ 3 & 18 & 18 \\ 4 & 20 & 20 \\ 5 & 26 & 24 \end{array}$$ a. $\quad$ Compute the difference value for each element. b. Compute $\bar{d}$ c. Compute the standard deviation $s_{d}$ d. Conduct a hypothesis test using $\alpha=.05 .$ What is your conclusion?

Statistics for Business and Economics

Assume that we want to identify a simple random sample of 12 of the 372 doctors practicing in a particular city. The doctors' names are available from a local medical organization. Use the eighth column of five-digit random numbers in Table 7.1 to identify the 12 doctors for the sample. Ignore the first two random digits in each five-digit grouping of the random numbers. This process begins with random number 108 and proceeds down the column of random numbers.

Essentials of Statistics for Business and Economics

Blackjack, or twenty-one as it is frequently called, is a popular gambling game played in Las Vegas casinos. A player is dealt two cards. Face cards, queens, and kings) and tens have a point value of $10 .$ Aces have a point value of 1 or $11 .$ A 52 -card deck contains 16 cards with a point value of 10 jacks, queens, kings, and tens) and four aces. a. What is the probability that both cards dealt are aces or 10 -point cards? b. What is the probability that both of the cards are aces? c. What is the probability that both of the cards have a point value of 10$?$ d. A blackjack is a 10 -point card and an ace for a value of $21 .$ Use your answers to parts $($ a), $(b),$ and $(c)$ to determine the probability that a player is dealt blackjack. (Hint: Part (d) is not a hypergeometric problem. Develop your own logical relationship as to how the hypergeometric probabilities from parts $(a),(b),$ and $(c)$ can be combined to answer this question.)

Blackjack, or twenty-one as it is frequently called, is a popular gambling game played in Las Vegas casinos. A player is dealt two cards. Face cards, queens, and kings) and tens have a point value of $10 .$ Aces have a point value of 1 or $11 .$ A 52 -card deck contains 16 cards with a point value of 10 jacks, queens, kings, and tens) and four aces. a. What is the probability that both cards dealt are aces or 10 -point cards? b. What is the probability that both of the cards are aces? c. What is the probability that both of the cards have a point value of 10$?$ d. A blackjack is a 10 -point card and an ace for a value of $21 .$ Use your answers to parts $($ a), $(b),$ and $(c)$ to determine the probability that a player is dealt blackjack. (Hint: Part (d) is not a hypergeometric problem. Develop your own logical relationship as to how the hypergeometric probabilities from parts $(a),(b),$ and $(c)$ can be combined to answer this question.)

Essentials of Modern Business Statistics

Questions asked

ANSWERED

Lucas Finney verified

Numerade educator

One of the new thrusts of quality control management is to examine the process by which a product is produced. This approach also applies to paperwork. In industries where large long-term projects are undertaken, days and even weeks may elapse as a change order makes its way through a maze of approvals before receiving final approval. This process can result in long delays and stretch schedules to the breaking point. Suppose a quality control consulting group claims that it can significantly reduce the number of days required for such paperwork to receive an approval. In an attempt to “prove” its case, the group selects five jobs for which it revises the paperwork system. The following data show the number of days required for a change order to be approved before the group intervened and the number of days required for a change order to be approved after the group instituted a new paperwork system. Before After 12 8 7 3 10 8 16 9 8 5 Use alpha = 0.05 to determine whether there was a significant drop in the number of days required to process paperwork to approve change orders. Assume that the differences in days are normally distributed. What is the appropriate critical value for this problem for alpha = 0.01? 4.6041 4.0321 3.3649 4.5407 3.7469

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Jon Southam verified

Numerade educator

For a ( t ) distribution with 18 degrees of freedom, find the area, or probability, in each region. (Round your answers to three decimal places.) (a) to the right of 1.734 0.050 (b) to the left of 2.552 (c) to the left of -2.101 (d) to the right of 1.330 (e) between -1.734 and 1.734 [ 0.900 ] (f) between -2.101 and 2.101

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Rashmi Sinha verified

Numerade educator

Do you dislike waiting in line? A supermarket chain has used computer simulation and information technology to reduce the average waiting time for customers at 2,300 stores. Using a new system, which allows the supermarket to better predict when shoppers will be checking out, the company was able to decrease average customer waiting time to just 21 seconds. (a) Assume that supermarket waiting times are exponentially distributed. Show the probability density function of waiting time at the supermarket. f(x)=left{egin{array}{lll} frac{1}{21} & , & x geq 0 \ 0 & , & ext { elsewhere } end{array} ight. (b) What is the probability that a customer will have to wait between 30 and 45 seconds? (Round your answer to four decimal places.) 0.0714 (c) What is the probability that a customer will have to wait more than 2 minutes? (Round your answer to four decimal places.) 0.0002

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Kari Hasz verified

Numerade educator

A travel association reported the domestic airfare (in dollars) for business travel for the current year and the previous year. Below is a sample of 12 flights with their domestic airfares shown for both years. Current Year | Previous Year --- | --- 345 | 303 526 | 451 420 | 462 216 | 206 285 | 275 405 | 432 635 | 585 710 | 650 605 | 545 517 | 547 570 | 496 610 | 580 (a) Formulate the hypotheses and test for a significant increase in the mean domestic airfare for business travel for the one-year period. H0: ??d < 0 Ha: ??d = 0 H0: ??d ? 0 Ha: ??d > 0 H0: ??d ? 0 Ha: ??d < 0 H0: ??d = 0 Ha: ??d ? 0

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Kari Hasz verified

Numerade educator

A market research firm used a sample of individuals to rate the purchase potential of a particular product before and after the individuals saw a new television commercial about the product. The purchase potential ratings were based on a 0 to 10 scale, with higher values indicating a higher purchase potential. The null hypothesis stated that the mean rating "after" would be less than or equal to the mean rating "before." Rejection of this hypothesis would show that the commercial improved the mean purchase potential rating. Use ? = 0.05 and the following data to test the hypothesis and comment on the value of the commercial. Individual Purchase Rating After Before 1 6 5 2 6 4 3 7 8 4 4 3 5 3 5 6 9 8 7 7 5 8 6 7 State the null and alternative hypotheses. (Use ?d = mean rating after - mean rating before.) H0: ?d = 0 Ha: ?d ? 0 H0: ?d ? 0 Ha: ?d > 0 H0: ?d ? 0 Ha: ?d = 0 H0: ?d ? 0 Ha: ?d = 0

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Kaushal Nair verified

Numerade educator

A consumer product testing organization uses a survey of readers to obtain customer satisfaction ratings for the nation's largest supermarkets. Each survey respondent is asked to rate a specified supermarket based on a variety of factors such as: quality of products, selection, value, checkout efficiency, service, and store layout. An overall satisfaction score summarizes the rating for each respondent with 100 meaning the respondent is completely satisfied in terms of all factors. Suppose sample data representative of independent samples of two supermarkets' customers are shown below. egin{tabular}{|c|c|} hline Supermarket 1 & Supermarket 2 \ hline( n_{1}=260 ) & ( n_{2}=300 ) \ hline ( ar{x}_{1}=83 ) & ( ar{x}_{2}=82 ) \ hline end{tabular} (a) Formulate the null and alternative hypotheses to test whether there is a difference between the population mean customer satisfaction scores for the two retailers. (Let ( mu_{1}= ) the population mean satisfaction score for Supermarket 1 's customers, and let ( mu_{2}= ) the population mean satisfaction score for Supermarket 2 's customers. Enter != for ( eq ) as needed.) ( mathrm{H}_{0}: ) ( H_{a} ) : (b) Assume that experience with the satisfaction rating scale indicates that a population standard deviation of 13 is a reasonable assumption for both retailers. Conduct the hypothesis test. Calculate the test statistic. (Use ( mu_{1}-mu_{2} ). Round your answer to two decimal places.) Report the ( p )-value. (Round your answer to four decimal places.) ( p )-value ( = ) At a 0.05 level of significance what is your conclusion?

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ANSWERED

Lucas Finney verified

Numerade educator

Suppose N = 10 and r = 3. Compute the hypergeometric probabilities for the following values of n and x. If the calculations are not possible, please select "not possible" from below drop-downs, and enter 0 in fields. Round your answers, if necessary. a. n = 4, x = 1 (to 2 decimals). b. n = 2, x = 2 (to 3 decimals). c. n = 2, x = 0 (to 4 decimals). d. n = 4, x = 2 (to 2 decimals). e. n = 4, x = 4 (to 2 decimals).

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Sanchit Jain verified

Numerade educator

The following table provides a probability distribution for the random variable ( oldsymbol{y} ). ( egin{array}{ll}y & f(y) \ 2 & 0.20 \ 4 & 0.30 \ 6 & 0.30 \ 9 & 0.20end{array} ) a. Compute ( E(y) ) (to 1 decimal). b. Compute ( operatorname{Var}(y) ) and ( sigma ) (to 2 decimals). ( operatorname{Var}(y) ) ( sigma )

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Ivan Kochetkov verified

Numerade educator

A simple random sample of 60 items resulted in a sample mean of 90. The population standard deviation is ? = 15. (a) Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.) 56.901 to 63.099 (b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.) to (c) What is the effect of a larger sample size on the interval estimate? A larger sample size provides a smaller margin of error. A larger sample size does not change the margin of error. A larger sample size provides a larger margin of error.

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ANSWERED

Kari Hasz verified

Numerade educator

A certain newspaper provides the net asset value, the year-to-date percent return, and the three-year percent return for 882 mutual funds at the end of 2017. Assume that a simple random sample of 12 of the 882 mutual funds will be selected for a follow-up study on the size and performance of mutual funds. Use the ninth column of the table of random numbers, beginning with 13554, to select the simple random sample of 12 mutual funds. Begin with mutual fund 554 and use the last three digits in each row of column 9 for your selection process. What are the numbers of the 12 mutual funds in the simple random sample? (Enter your answers as a comma-separated list.)

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