Question

The compressive strength of concrete is normally distributed. A random sample of 11 concrete specimens from...

The compressive strength of concrete is normally distributed. A random sample of 11 concrete specimens from Factory 1 yields a sample mean equal to 1,221.3 pounds per square inch (psi) and a sample variance of 882.0 psi2. A random sample of 11 concrete specimens from Factory 2 yields a sample mean equal to 1,441.2 psi and a sample variance of 856.1 psi2.  

If you do a test of hypothesis to see if the means of the concretes from Factory 1 and Factory 2 are equal or not, what is the numerical value of the test statistic? Express your answer to two decimal places.

Math   Statistics-And-Probability   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

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
The compressive strength of concrete is normally distributed with μ = 2500 psi and σ =...
The compressive strength of concrete is normally distributed with μ = 2500 psi and σ = 50 psi. A random sample of n = 5 specimens is taken. What is the standard error of the sample mean? A) 2500 B) 10 C) 22.36 D) 50
Suppose that the compressive strength of concrete is normally distributed with an unknown mu and a...
Suppose that the compressive strength of concrete is normally distributed with an unknown mu and a known sigma of 40 (pounds per square inch). A random sample of size 19 has sample mean 1376. Construct a 92% confidence interval (as crazy and unlikely as it seems to create a 92% CI) for the population mean. Give answer to one decimal place.
We measured the compressive strength for n = 16 specimens of concrete. Using the mean and...
We measured the compressive strength for n = 16 specimens of concrete. Using the mean and standard deviation and assuming a normal population, we computed the following confidence interval [2271.7688, 2308.2312]. This interval is a confidence interval for the mean compressive strength at a level of confidence of 90%. We are told the the sample mean is x = 2290. What is the value of the sample standard deviation s?
Testing of a given concrete sample has yielded a normal distribution with a mean compressive strength...
Testing of a given concrete sample has yielded a normal distribution with a mean compressive strength of 3200 psi with a standard deviation of 275 psi. You require a compressive strength of at least 2950 psi.  What is the probability that this concrete meets your needs?
The accompanying data is on cube compressive strength (MPa) of concrete specimens. 112.5      97.0     ...
The accompanying data is on cube compressive strength (MPa) of concrete specimens. 112.5      97.0      92.6      86.0      102.0 99.1      95.8      103.5      89.0      86.6 (a) Is it plausible that the compressive strength for this type of concrete is normally distributed? The normal probability plot is not acceptably linear, suggesting that a normal population distribution is plausible. The normal probability plot is acceptably linear, suggesting that a normal population distribution is plausible.     The normal probability...
A sample of concrete specimens of a certain type is selected, and the compressive strength of...
A sample of concrete specimens of a certain type is selected, and the compressive strength of each specimen is determined. The mean and standard deviation are calculated as x = 4000 and s = 300, and the sample histogram is found to be well approximated by a normal curve. (a)Approximately what percentage of the sample observations are between 3700 and 4300? (Round the answer to the nearest whole number.) Approximately  % (b) Approximately what percentage of sample observations are outside the...
The data in the Excel sheet labeled 'Concrete' represent the compressive ​strength, in thousands of pounds...
The data in the Excel sheet labeled 'Concrete' represent the compressive ​strength, in thousands of pounds per square inch​ (psi), of 20 samples of concrete taken two and seven days after pouring. At the 0.01 level of​ significance, is there evidence that the mean strength is lower at two days than at seven​ days? What test will you use? What is the p-value? Reject Ho? Is there evidence of a lower strength? Two days Seven days Sample 1 3.8 4.07...
A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean...
A synthetic fiber used in manufacturing carpet has tensile strength that is normally distributed with mean 75.5 psi and standard deviation 3.5 psi. Find the probability that a random sample of n=7 fiber specimens will have a sample mean tensile strength that exceeds 75.8 psi. Round your answer to two decimal places.
As concrete​ cures, it gains strength. The following data represent the​ 7-day and​ 28-day strength in...
As concrete​ cures, it gains strength. The following data represent the​ 7-day and​ 28-day strength in pounds per square inch​ (psi) of a certain type of concrete. 7-Day_Strength_(psi)_-_x   28-Day_Strength_(psi)_-_y 2300   4070 3380   5020 2620   4190 3390   5220 3330   4850 (a) Treating the​ 7-day strength as the explanatory​ variable, x, use technology to determine the estimates of β0 and β1. β0≈b0=1753.9​ (Round to one decimal place as​ needed.) β1≈b1=0.9707 ​(Round to four decimal places as​ needed.) Se=150.6 ​(Round to one decimal...
As concrete​ cures, it gains strength. The following data represent the​ 7-day and​ 28-day strength in...
As concrete​ cures, it gains strength. The following data represent the​ 7-day and​ 28-day strength in pounds per square inch​ (psi) of a certain type of concrete. 7-Day_Strength_(psi)_-_x   28-Day_Strength_(psi)_-_y 2300   4070 3380   5020 2620   4190 3390   5220 3330   4850 (a) Treating the​ 7-day strength as the explanatory​ variable, x, use technology to determine the estimates of β0 and β1. β0≈b0=1753.9 ​ (Round to one decimal place as​ needed.) β1≈b1=0.9707 ​ (Round to four decimal places as​ needed.) Se=150.6 ​(Round to...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT