A sample that does not accurately represent the population is a ________

Information from a sample of 157 restaurant bills collected at the First Crush bistro is available in RestaurantTips. Two interv

wolverine [178]

Answer:

a) The 99% confidence interval is interval B: 3.35 to 4.35

The 90% confidence interval is interval A: 3.55 to 4.15.

b) Check Explanation.

Step-by-step explanation:

Confidence Interval for the population mean is basically an interval of range of values where the true population mean can be found with a certain level of confidence.

Mathematically,

Confidence Interval = (Sample mean) ± (Margin of error)

Margin of Error is the width of the confidence interval about the mean.

It is given mathematically as,

Margin of Error = (Critical value) × (standard Error of the mean)

Critical value is obtained from either the t-distribution or the z-distribution tables. It depends on sample size and for smaller sample sizes, whether there is information provided for the population mean and standard deviation.

But whether z-distribution or t-distribution, the critical value increases as the confidence level increases.

Hence, the critical value for the 99% confidence level will be higher than the critical value for the 90% confidence level.

And since all the other parameters that determine the confidence interval and it's width (sample mean and the standard error of the mean) are the same for the 90% and the 99% confidence interval, the larger critical value for the 99% confidence interval means that it has the bigger width.

Hence, of the two intervals given,

Interval A: 3.55 to 4.15

Interval B: 3.35 to 4.35

The larger interval, (3.35, 4.35) is the 99% confidence interval and the smaller interval, (3.55, 4.15) is the 90% confidence interval.

b) The data required for this second part isn't available, but the answer for the confidence interval can be obtained using the steps I have given above and below.

Like I have given above,

Confidence Interval = (Sample mean) ± (Margin of error)

Margin of Error = (Critical value) × (standard Error of the mean)

The sample mean and the standard error of the mean are obtained from the sample data (which is missing).

Sample mean = (Σx)/N

x = each variable

N = number of variables = 20

Standard error of the mean = σₓ = (σ/√n)

σ = standard deviation (obtained from the sample data)

90% critical value for sample size of 20 = 1.73

99% critical value for sample size of 20 = 2.86

Hope this Helps!!!

4 0

4 years ago

Bridget reads 5 pages of her book per day 4 days per week for several weeks.

Likurg_2 [28]

The correct answer would be (4*5)w because you would multiple the number of pages that she reads per week then you multiply that by how many weeks she reads.

8 0

3 years ago

Read 2 more answers

Can someone help me please??? Four questions!

Tamiku [17]

2x-2x+4=6
4=6
and since there's no such things im gonna say D.no solution

4 0

4 years ago

can anyone help tech me how to solve for tax and tip. im going to 6th grade and trying to get into the advanced group but I don'

baherus [9]

If something isn't clear or you're still confused about, let me know in the comments.

Step-by-step explanation:

Okay, here's my best try.

Suppose you have a bill for $8.45

If you are asked to add, say, 8% tax, you must calculate 8 percent of 8.45 and then add it to 8.45.

Begin by converting 8% to decimals by dividing by 100.

$\frac{8}{100}=0.08$ 8% is 0.08 in decimal form.

To calculate a percentage of a number, you multiply the decimal percent by the number; example:

$0.08(8.45)$ 8.45 is being multiplied by 0.08. The result is: 0.676. (this is the tax; however you have to round up to two decimal places: $0.68)

After finding the tax amount, if you are asked to add it to the bill, you have to add it to the original bill; in this case, $8.45

This would be: 0.68+8.45=9.13.

Therefore, the total bill after tax is for $9.13

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With tips is the same thing, however, you can have 2 situations.

Situation 1: You are asked to calculate 15% tip of total bill.

In this situation, you can do the same we do to calculate tax.

Convert the percentage to decimal by dividing by 100.

$\frac{15}{100}=0.15$

and multiply it by the original bill.

$0.15(8.45)=1.2675$ . Rounding up, this would be $1.27 for tip.

If you were to add it to the original bill, simply sum.

$8.45+1.27=9.72$

The total bill after tips is for $9.72

Situation 2: You are asked to calculate 15% tip of the total bill with a tax of 8% included.

In this situation, you must first calculate the total bill with the tax added, like we did above; we got a bill for $9.13 (Tax included)

Then you can calculate 15% tip of this new bill that has tax included.

Convert

$\frac{15}{100}=0.15$

Multiply by the new bill (because this is the one that includes tax)

$0.15(9.13)=1.3695$ Round up.... $1.37 for tips.

If you are asked to give a total amount of money including tax and tips, add this to the bill.

9.13+1.37=10.50

This bill would be for $10.50

3 0

3 years ago

How many degrees are in a full rotation about a center point?

GarryVolchara [31]

The answer would be 360 degrees

6 0

3 years ago

Read 2 more answers

A sample that does not accurately represent the population is a _________.