Answer:
For 99% of confidence interval is 67.5±1.3524
Step-by-step explanation:
Given:
Mean height =67.5 inches
Standard deviation:2.1 inches
Z at 99%.
No of samples 16.
To find:
confidence interval
Solution:
We have formula for confidence interval,
=mean ±Z*{standard deviation/sqrt(no.of observation)}
Now
Z=99%
has standard value as ,
Z=2.576
Confidence interval= mean±Z{standard deviation/sqrt(No. of samples)}
=67.5±2.57{(2.1/sqrt(16)}
=67.5±2.576(2.1/4)
=67.5±1.3524
Answer:
The margin of error is of 0.11 carats.
The 95% confidence interval for the true mean weight of all sapphires produced by the new process is between 6.64 and 6.86 carats. The interpretation is that we are 95% sure that the true weight of all sapphires produced by the company using the new process is between these two values.
Step-by-step explanation:
We have the standard deviation for the sample, which means that we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 37 - 1 = 36
95% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 36 degrees of freedom(y-axis) and a confidence level of
. So we have T = 2.0281
The margin of error is:

In which s is the standard deviation of the sample and n is the size of the sample.
The margin of error is of 0.11 carats.
The lower end of the interval is the sample mean subtracted by M. So it is 6.75 - 0.11 = 6.64 carats
The upper end of the interval is the sample mean added to M. So it is 6.75 + 0.11 = 6.86 carats.
The 95% confidence interval for the true mean weight of all sapphires produced by the new process is between 6.64 and 6.86 carats. The interpretation is that we are 95% sure that the true weight of all sapphires produced by the company using the new process is between these two values.
A digit in the ten thousand place is 10x times larger than a digit in the thousands place.
We can see that here- 1,000 x 10 = 10,000
Hey!
Let p = cost of a pen
<span>Let n = cost of a notebook </span>
<span>The info in the question leads to two equations: </span>
<span>1) 2p + 3n = 5.55 </span>
<span>2) p + 2n = 3.50 </span>
<span>Multiply equation 2) by 2 to get the new system of equations </span>
<span>1a) 2p + 3n = 5.55 </span>
<span>2a) 2p + 4n = 7.00 </span>
<span>Subtract equation 1a) from equation 2a) to get </span>
<span>n = 1.45 ...................... that's the cost of one notebook </span>
<span>~~~~~~~~ </span>
<span>To check, you could go on to figure out p, which turns out to be 0.60 . Put in those values of n and p into the original equations to verify.</span>
Hope this helps! ~Nadia~