Question

In: Statistics and Probability

1. A firm would like to know the average time its workers spend on a certain...

1. A firm would like to know the average time its workers spend on a certain task. The firm takes a sample of 35 workers and finds that they take, on average, 13 minutes to complete the task, with a sample standard deviation of 3 minutes. Construct a 95% confidence interval for the population mean.

a) State the critical value:

b) Calculate the margin of error (round to the thousandths place):

c) State the lower and upper values of the confidence interval:

Expert Solution

Solution :

Given that,

= 13

s =3

n =35

Degrees of freedom = df = n - 1 =35 - 1 = 34

At 95% confidence level the t is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2= 0.05 / 2 = 0.025

t /2,df = t0.025,34 = 2.032 ( using student t table)

Margin of error = E = t/2,df * (s / $\sqrt$ n)

= 2.032* (3 / $\sqrt$ 35)

= 1.030

The 95% confidence interval is,

- E < < + E

13 - 1.030< <13 +1.030

11.970 < < 14.030

(11.970 , 14.030)

orchestra answered 2 years ago

A firm would like to know the average time its workers spend on a certain task. The...

A firm would like to know the average time its workers spend on a certain task. The firm takes a sample of 35 workers and finds that they take, on average, 13 minutes to complete the task, with a sample standard deviation of 3 minutes. Construct a 95% confidence interval for the population mean. a) State the critical value: b) Calculate the margin of error (round to the thousandths place): c) State the lower and upper values of the confidence interval:

In a certain small city, the Mayor would like to know the average income of 25000...

In a certain small city, the Mayor would like to know the average income of 25000 families. A survey is conducted and took a simple random sample of 900 families. The average income of these families is 64,500 dollars. The SD of the 900 incomes is $32,500. Thus, the Mayor concludes that the average income of the city is...... give or take …... The 95 percent confident interval for the average incomes of all the families is from..... dollars to...…....

4. A firm would like to know the proportion of its employees that expect to receive...

4. A firm would like to know the proportion of its employees that expect to receive a raise within the next year. The firm surveys 150 employees and finds that 60 expect a raise. Construct a 90% confidence interval for the population proportion. a) What is the sample proportion? b) State the critical value: c) Calculate the margin of error (round to the thousandths place): d) State the lower and upper values for the confidence interval:

A firm would like to know the proper portion of its employees that expect to receive...

A firm would like to know the proper portion of its employees that expect to receive a raise within the next year the firm surveys 150 employees and find that 60 expect a raise construct a 90% confidence interval for the population proportion a) what is the sample proportion? b) State the critical value c) calculate the margin of error round to the thousands place d) State the lower and upper values for the confidence interval

A firm would like to know the proportion of it employees that expect to receive a...

A firm would like to know the proportion of it employees that expect to receive a raise within the next year the firm survey is 150 employees and finds that 60 expect to raise construct a 90% confidence interval for the population proportion a) what is the sample proportion b) State the critical value c) calculate the margin of error d) State the lower and upper values for the confidence interval

1. Choose a firm that you want to know more about or that you would like...

1. Choose a firm that you want to know more about or that you would like to work for in the future. Research the firm and it's supply chain. Consider this from the raw materials to the end user and explain and define the firms supply chain. 2. How could the firm improve it's supply chain? Consider the Pareto Optimum. 3. Would a vertical merger be an option for the supply chain? What type of efficiencies may be gained? What...

How much time, on average, would a server need to spend on a customer to achieve...

How much time, on average, would a server need to spend on a customer to achieve a service rate of 8 customers per hour? (Round your answer to 2 decimal places.)

How much time on average would a server need to spend on a customer to achieve...

How much time on average would a server need to spend on a customer to achieve a service rate of 30 customers per hour? (round answer to 2 decimal places)

The manager of a store would like to know if the average daily sales (measured in...

The manager of a store would like to know if the average daily sales (measured in dollars) through her website are any different than her in-store sales. The data has been collected on 51 days on website and in store. Perform an analysis at 5% significance level. Start by stating the hypothesis. Online In-Store 805.45 1400.76 780.27 969.27 927.79 1049.61 812.86 1453.6 550.91 876.72 901.07 1119.49 869.76 976.6 867.17 1017.76 801.91 482.12 973.15 1149.21 746.65 809.37 980.25 968.43 892.53 1077.45...

13. A manager wants to know whether customers in Taiwan, on average, would spend more than...

13. A manager wants to know whether customers in Taiwan, on average, would spend more than $2,000 per month on the service that is similar to what her company provides. The following information regarding the consumer behavior of 49 customers was provided by the marketing research team: sample mean = $2,400 and sample standard deviation = $1,800. Using the sample information provided and 0.05 significance level, determine the critical value and calculate the value of the test statistic. A. Critical...