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xenn [34]
2 years ago
6

At the end of the quarter, sara knows she got a perfect score on 3 out of 7 of her history quizzes. How many total quizzes did s

he take during the quarter if she has 9 perfect scores?
Mathematics
1 answer:
Karolina [17]2 years ago
3 0

Answer:

11

Step-by-step explanation:

You might be interested in
Alyssa had $289 to spend on seven books after buying them she had $16 how much did each book cost
Mazyrski [523]

Answer:each book cost 39 dollars

Step-by-step explanation:

Since she had 16 dollars left over afterwords subtract 16 from 289 which leaves you with 273. then take the 273 and divide by the 7 books she bout whic will become 39 dollars therefore each book cost 39 dollars

6 0
3 years ago
Read 2 more answers
An educator claims that the average salary of substitute teachers in school districts is less than $60 per day. A random sample
valentina_108 [34]

Answer:

t=\frac{58.875-60}{\frac{5.083}{\sqrt{8}}}=-0.626    

The degrees of freedom are given by:

df=n-1=8-1=7  

The p value would be given by:

p_v =P(t_{(7)}  

Since the p value is higher than 0.1 we have enough evidence to FAIl to reject the null hypothesis and we can't conclude that the true mean is less than 60

Step-by-step explanation:

Information given

60, 56, 60, 55, 70, 55, 60, and 55.

We can calculate the mean and deviation with these formulas:

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

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

Replacing we got:

\bar X=58.875 represent the mean

s=5.083 represent the sample standard deviation for the sample  

n=8 sample size  

\mu_o =60 represent the value that we want to test

\alpha=0.1 represent the significance level

t would represent the statistic

p_v represent the p value

Hypothesis to test

We want to test if the true mean is less than 60, the system of hypothesis would be:  

Null hypothesis:\mu \geq 60  

Alternative hypothesis:\mu < 60  

The statistic would be given by:

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

Replacing the info we got:

t=\frac{58.875-60}{\frac{5.083}{\sqrt{8}}}=-0.626    

The degrees of freedom are given by:

df=n-1=8-1=7  

The p value would be given by:

p_v =P(t_{(7)}  

Since the p value is higher than 0.1 we have enough evidence to FAIl to reject the null hypothesis and we can't conclude that the true mean is less than 60

3 0
3 years ago
Jacob is a plumber. Due to increased material costs, he puts all his prices up by 7%. He now chargers R320 per hour for her serv
Lorico [155]

Answer:

R290.1

Step-by-step explanation:

Let

x = charge before he put his prices up

New charge = R320

Percentage increase in price = 7%

x + 7% of x = 320

x + 0.07 * x = 320

x + 0.07x = 320

1.07x = 320

x = 320/1.07

x = 299.06542056074

Approximately

x = R290.1

Charge before he put his prices up = R290.1

4 0
2 years ago
The average cost of tuition plus room and board at small private liberal arts colleges is reported to be less than $18,500 per t
lys-0071 [83]

Answer:

The null and alternative hypothesis for this study are:

H_0: \mu=18500\\\\H_a:\mu< 18500

The null hypothesis is rejected (P-value=0.004).

There is enough evidence to support the claim that the average cost of tuition plus room and board at small private liberal arts colleges is  less than $18,500 per term.

Step-by-step explanation:

This is a hypothesis test for the population mean.

The claim is that the average cost of tuition plus room and board at small private liberal arts colleges is  less than $18,500 per term.

Then, the null and alternative hypothesis are:

H_0: \mu=18500\\\\H_a:\mu< 18500

The significance level is 0.05.

The sample has a size n=150.

The sample mean is M=18200.

The standard deviation of the population is known and has a value of σ=1400.

We can calculate the standard error as:

\sigma_M=\dfrac{\sigma}{\sqrt{n}}=\dfrac{1400}{\sqrt{150}}=114.31

Then, we can calculate the z-statistic as:

z=\dfrac{M-\mu}{\sigma_M}=\dfrac{18200-18500}{114.31}=\dfrac{-300}{114.31}=-2.624

This test is a left-tailed test, so the P-value for this test is calculated as:

P-value=P(z

As the P-value (0.004) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the average cost of tuition plus room and board at small private liberal arts colleges is  less than $18,500 per term.

3 0
3 years ago
Terry had 400 inches of ribbon before he cut pieces of ribbon that were 8 inches long how many 15 inch pieces can terry cut fro
Nikitich [7]
This could be wrong but the remaining pieces he can cut is 3 because if you divide 400 with 8 , it’s 35 as the answer, so then subtract 35 with 15 till you can subtract 15 from it
4 0
2 years ago
Read 2 more answers
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