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SpyIntel [72]
3 years ago
14

Miranda is taking tennis lessons in one lesson, she returned 36 balls out of all the balls served to her. If she returned 40% of

the balls, how many balls were
served to her?
Mathematics
1 answer:
iragen [17]3 years ago
4 0

Answer:

90 balls

Step-by-step explanation:

Set up proportion

36/x = 40/100

Cross multiply: 40x=3600

Solve for x

x=90

To check work:

40 percent of 90 would be 36

90(0.4)=36

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Fowle Marketing Research Inc., bases charges to a client on the assumption that telephone surveys can be completed in a mean tim
sergejj [24]

Answer:

a) Null hypothesis:\mu \leq 15  

Alternative hypothesis:\mu > 15  

b) t=\frac{17-15}{\frac{4}{\sqrt{35}}}=2.958      

c) p_v =P(t_{34}>2.958)=0.0028    

d) If we compare the p value and the significance level given \alpha=0.01 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 15 at 1% of signficance.  

Step-by-step explanation:

Data given and notation  

The sample mean is given by:

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

And the sample deviation is:

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

\bar X=17 represent the sample mean    

s=4 represent the sample standard deviation

n=35 sample size  

\mu_o =15 represent the value that we want to test  

\alpha=0.01 represent the significance level for the hypothesis test.  

z would represent the statistic (variable of interest)  

p_v represent the p value for the test (variable of interest)  

Part a State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the mean is less or equal than 15, the system of hypothesis would be:  

Null hypothesis:\mu \leq 15  

Alternative hypothesis:\mu > 15  

Since we don't  know the population deviation, is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:  

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

t-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".  

Part b Calculate the statistic  

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

t=\frac{17-15}{\frac{4}{\sqrt{35}}}=2.958  

Part c P-value  

The degrees of freedom are given by:

df = n-1= 35-1=34

Since is a right tailed test the p value would be:  

p_v =P(t_{34}>2.958)=0.0028  

Part d Conclusion  

If we compare the p value and the significance level given \alpha=0.01 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the true mean is higher than 15 at 1% of signficance.  

7 0
3 years ago
Please answer thoroughly
aleksklad [387]

Answer:

Part A: 2k(2c2+5(2)-8c-20)

Part B: sorry i don't know how to do this part

Step-by-step explanation:

Part A, you divide each number by 2 first so you get a simplified version of each number. Then, you will quickly realize that the varible k is similar in all of the numbers then you remove that and put it with the 2 outside the (). Hope you understood my explination.

7 0
3 years ago
Help me plz asap if you can
Andrej [43]
Your answer for this is 17 hope i helped
8 0
3 years ago
Read 2 more answers
The number of fans who attended a softball game increased from 1,200 for the first game to 1,500 for the second game. How many f
erma4kov [3.2K]
1875 fans will attend
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3 years ago
Write an expression to represent the perimeter of the figure.
r-ruslan [8.4K]

Answer:

5x + 2y + z

Step-by-step explanation:

The perimeter of a polygon is the sum of the lengths of all the sides of the polygon. This polygons has 8 sides. Their lengths are:

x, x, x, x, x, y, y, z

The perimeter of the polygon is the sum of the lengths shown above.

perimeter = x + x + x + x + x + y + y + z

The expression above can be simplified by combining like terms.

perimeter = 5x + 2y + z

4 0
3 years ago
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