Question

A company wants to examine the average operation time for a process. Two methods were used....

A company wants to examine the average operation time for a process. Two methods were used. A random sample of 40 for the first method gives an average mean time of 20.5 minutes with variance of 3 minutes. A random sample of 50 for the second method gives an average mean time of 17.6 minutes with variance of 4 minutes. (Use normal distribution with variance known)

  1. Determine the 95% confidence interval for the difference between the means
  2. At alpha =0.05 can we conclude that there is a difference in the mean times? (Hypothesis test)
Math   Statistics-And-Probability   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

a) 95% confidence interval for the difference between the means

is 95% confidence interval for the difference between the means.

b) NULL HYPOTHESIS H0:

ALTERNATIVE HYPOTHESIS Ha:

alpha=0.05

Z critical=1.96

Since Z cal is greater than Z critical therefore we reject null hypothesis H0 and conclude that there is difference in mean times.

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
An investigation is undertaken to examine the average times to relief from headache pain under two...
An investigation is undertaken to examine the average times to relief from headache pain under two entirely different treatments: Medication vs. Relaxation. Patients suffering from chronic headaches are enrolled in a study and randomly assigned to one of the two treatment groups. Patients are instructed to either take the assigned medication or to perform the relaxation exercises at the onset of their next headache. They are also instructed to record the time, in minutes, until the headache pain is resolved....
An industrial designer wants to determine the average amount of time it takes an adult to...
An industrial designer wants to determine the average amount of time it takes an adult to assemble an "easy to assemble" toy. A sample of 16 times yielded an average time of 19.92 minutes, with a sample standard deviation of 5.73 minutes. assuming normality of assembly times, the 95% confidence interval for the mean assembly time is ?
Two methods have been developed to determine the nickel content of steel. In a sample of...
Two methods have been developed to determine the nickel content of steel. In a sample of five replications of the first method on a certain kind of steel, the average measurement was 3.16% with a standard deviation of 0.042%. The average of seven replications of the second method was 3.24% and a standard deviation of 0.048%. Assume that it is known that the population variances are equal. Using hypothesis testing, can we conclude that there is a difference in the...
A customer service representative was interested in comparing the average time (in minutes) customers are placed...
A customer service representative was interested in comparing the average time (in minutes) customers are placed on hold when calling Southern California Edison (SCE) and Southern California Gas (SCG) companies. The representative obtained two independent random samples and calculated the following summary information: SCE SCG Sample Size 9 12 Sample Mean 3.2 minutes 2.8 minutes Sample Standard Deviation 0.5 minutes 0.7 minutes Test whether there is a significant difference in average time a customer is on hold between the two...
A local pizza place claims that they average a delivery time of 7.32 minutes. To test...
A local pizza place claims that they average a delivery time of 7.32 minutes. To test this claim, you order 11 pizzas over the next month at random times on random days of the week. You calculate the average delivery time and sample standard deviation from the 11 delivery times (minutes), and with the sample mean and sample standard deviation of the time (minutes), you create a 95% confidence interval of (7.648, 9.992). (delivery time is normally distributed) a. What...
A client wants to determine whether there is a significant difference in the time required to...
A client wants to determine whether there is a significant difference in the time required to complete a program evaluation with the three different methods that are in common use. Suppose the times (in hours) required for each of 18 evaluators to conduct a program evaluation follow. Method 1 Method 2 Method 3 68 64 58 72 73 65 69 79 66 77 68 55 75 74 56 74 70 64 Use α = 0.05 and test to see whether...
A client wants to determine whether there is a significant difference in the time required to...
A client wants to determine whether there is a significant difference in the time required to complete a program evaluation with the three different methods that are in common use. Suppose the times (in hours) required for each of 18 evaluators to conduct a program evaluation follow. Method 1 Method 2 Method 3 65 62 55 74 73 69 67 77 68 76 65 59 79 72 58 72 70 62 Use α = 0.05 and test to see whether...
A pencil company wants to compare the variation in the circumference of their product from two...
A pencil company wants to compare the variation in the circumference of their product from two different production methods. They take a random sample of 57 pencils produced from method 1 and they take a random sample of 65 pencils from method 2. They determine that variance number one equals 26.2 and variance number 2 equals 13.1. The company wants to determine if the population variance from method 1 is greater than the population variance from method 2. Let alpha...
Waiting time for checkout line at two stores of a supermarket chain were measured for a...
Waiting time for checkout line at two stores of a supermarket chain were measured for a random sample of customers at each store. The chain wants to use this data to test the research (alternative) hypothesis that the mean waiting time for checkout at Store 1 is lower than that of Store 2. (12 points) Store 1 (in Seconds) Store 2 (in Seconds) 470 375 394 319 167 266 293 324 187 244 115 178 195 279 400 289 228...
An automobile assembly line operation has a scheduled mean completion time, μ, of 13.5 minutes. The...
An automobile assembly line operation has a scheduled mean completion time, μ, of 13.5 minutes. The standard deviation of completion times is 1.4 minutes. It is claimed that, under new management, the mean completion time has decreased. To test this claim, a random sample of 26 completion times under new management was taken. The sample had a mean of 13.2 minutes. Assume that the population is normally distributed. Can we support, at the 0.05 level of significance, the claim that...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT