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sammy [17]
3 years ago
15

At a school, 40% of sixth grade students said that hip-hop is their favorite kind of music. If 100 sixth grade students prefer h

ip-hop music, how many sixth grade students are at school
Mathematics
2 answers:
valina [46]3 years ago
7 0
60 kids like hip hop

posledela3 years ago
5 0
250 students are in the 6th grade
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Consider a chemical company that wishes to determine whether a new catalyst, catalyst XA-100, changes the mean hourly yield of i
kolezko [41]

Answer:

Null hypothesis:\mu = 750  

Alternative hypothesis:\mu \neq 750  

t=\frac{811-750}{\frac{19.647}{\sqrt{5}}}=6.943  

p_v =2*P(t_{4}>6.943)=0.00226  

If we compare the p value and a significance level assumed \alpha=0.05 we see that p_v so we can conclude that we reject the null hypothesis, and the actual true mean is significantly different from 750 pounds per hour.  

Step-by-step explanation:

Data given and notation

Data:    801, 814, 784, 836,820

We can calculate the sample mean and sample deviation with the following 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}}

\bar X=811 represent the sample mean  

s=19.647 represent the standard deviation for the sample

n=5 sample size  

\mu_o =750 represent the value that we want to test  

\alpha represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

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

State the null and alternative hypotheses to be tested  

We need to conduct a hypothesis in order to determine if the mean is different from 750 pounds per hour, the system of hypothesis would be:  

Null hypothesis:\mu = 750  

Alternative hypothesis:\mu \neq 750  

Compute the test statistic  

We don't know the population deviation, so for this case 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".  

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

t=\frac{811-750}{\frac{19.647}{\sqrt{5}}}=6.943  

Now we need to find the degrees of freedom for the t distirbution given by:

df=n-1=5-1=4

What do you conclude?  

Compute the p-value  

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

p_v =2*P(t_{4}>6.943)=0.00226  

If we compare the p value and a significance level assumed \alpha=0.05 we see that p_v so we can conclude that we reject the null hypothesis, and the actual true mean is significantly different from 750 pounds per hour.  

4 0
3 years ago
Ms. O'Conner took a poll of 80 students to find out how they get to school. How many more students get to school on a bus than i
il63 [147K]

Answer:

I need the dull question

Step-by-step explanation:

4 0
3 years ago
Sum of two numbers is 84. If one of the numbers exceeds the other by 12, the numbers are
djverab [1.8K]

Answer:

54 and 30

Step-by-step explanation:

84÷2=42-12=30

42+12=54

5 0
3 years ago
I need help on this question
tatiyna
It is a right agn have a good day
6 0
3 years ago
Xác suất xảy ra môt sự kiện là 0.3. Xác suất để sự kiện đó không xảy ra là?
hodyreva [135]

Câu trả lời:

0,7

Giải thích từng bước:

Xác suất để một sự kiện xảy ra = 0,3

Cho sự kiện = A

P (A) = 0,3

Xác suất mà sự kiện không xảy ra có thể thu được bằng cách sử dụng quy tắc bổ sung;

P (A ') = 1 - P (A)

Vì thế,

P (A ') = 1 - 0,3 = 0,7

3 0
3 years ago
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