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anzhelika [568]

4 years ago

9

A bakery sold 101 cupcakes in one day. The head baker predicted he would sell 81 cupcakes that day. What was the percent error o

f the baker's prediction? *

1 answer:

Hoochie [10]4 years ago

6 0

Answer:

19.8% is the percent error of the baker's prediction.

Step-by-step explanation:

We are given the following in the question:

Total number of cupcakes sold in 1 day = 101

Predicted number of cupcakes sold = 81

We have to find the percent error of the baker's prediction.

Percentage error =

$=\dfrac{\text{Actual value - Predicted value}}{\text{Actual values}}\times 100\%$

Putting values, we get

$=\dfrac{101-81}{101}\times 100\%\\\\=19.8\%$

Thus, 19.8% is the percent error of the baker's prediction.

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23. A certain type of gasoline is supposed to have a mean octane rating of at least 90. Suppose measurements are taken on of 5 r

Nostrana [21]

Answer:

a) $p_v =P(Z$

b) Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

c) $P(\bar X >90)=1-P(Z$

$1-P(Z$

d) For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

Step-by-step explanation:

Previous concepts and data given

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

We can calculate the sample mean and deviation with the following formulas:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

$s=\sqrt{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}$

$\bar X=88.96$ represent the sample mean

$s=1.011$ represent the sample standard deviation

n=5 represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is less than 90, the system of hypothesis would be:

Null hypothesis: $\mu \geq 90$

Alternative hypothesis: $\mu < 90$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{88.96-90}{\frac{0.8}{\sqrt{5}}}=-2.907$

Part a

P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=5-1 = 4$

Then since is a left tailed test the p value would be:

$p_v =P(Z$

Part b

Since $p_v$ we can reject the null hypothesis at the significance level given. So based on this we can commit type of Error I.

Because Type I error " is the rejection of a true null hypothesis".

Part c

We want this probability:

$P(\bar X$

The best way to solve this problem is using the normal standard distribution and the z score given by:

$z=\frac{x-\mu}{\frac{\sigma}{\sqrt{n}}}$

If we apply this formula to our probability we got this:

$P(\bar X >90)=1-P(Z$

$1-P(Z$

Part d

For this case we need a z score that accumulates 0.02 of the area on the right tail and 0.98 on the left tail and this value is z=2.054

And we can use this formula:

$2.054=\frac{90-89}{\frac{0.8}{\sqrt{n}}}$

And if we solve for n we got:

$n = (\frac{2.054 *0.8}{1})^2=2.7 \approx 3$

7 0

3 years ago

A local food truck specializes in gourmet grilled cheese sandwiches. Each month, the owners of the truck have a constant total o

Serggg [28]

Answer:

A. (9 - 2.25)s ≥ 5,400

B. They will have to sell more than 800 sandwiches per month. I first started by solving the parentheses which is 6.75. Then I divided 5,400 by 6.75 to get 800.

C. It will now end up looking like this: (8 - 2.25)s ≥ 5,400. Then it will be 5.75. Then divide 5,400 by 5.75. Then you end up with 939.13. You have to round up when you are talking about inequalities with money so it will be 940. So they will have to sell 140 more sandwiches during that month.

Step-by-step explanation:

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3 years ago

Which statement is true about the function f(x)= StartRoot negative x EndRoot?

UNO [17]

Answer:

The domain of the graph is all real numbers less than or equal to 0

Step-by-step explanation:

we have the function

$f(x)=\sqrt{-x}$

we know that

The radicand must be positive

so

$-x \geq 0$

Solve for x

Multiply by -1 both sides

$x\leq 0$

The domain is the interval ------> (-∞,0]

All real numbers less than or equal to zero

The range of the function is the interval -----> [0,∞)

$f(x)\geq 0$

see the attached figure to better understand the problem

All real numbers greater than or equal to zero

<em><u>Verify each statement</u></em>

case 1) The domain of the graph is all real numbers

The statement is false

Because, the domain is all real numbers less than or equal to zero

case 2) The range of the graph is all real numbers

The statement is false

Because, the range is all real numbers greater than or equal to zero

case 3) The domain of the graph is all real numbers less than or equal to 0

The statement is true

case 4) The range of the graph is all real numbers less than or equal to 0

The statement is false

Because, the range is all real numbers greater than or equal to zero

4 0

3 years ago

Read 2 more answers

A rectangle is 3 cm long and 2 cm wide

Nimfa-mama [501]

Answer:

Perimeter = 100mm

Area = 60mm

Step-by-step explanation:

P= (3x2) + (2x2) =10cm

10mm to 1cm

10cm x 10 = 100mm

A= b x h

= 3 x 2

=6cm

6x10=60mm

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anzhelika [568]

Have Trina Sosa
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