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maksim [4K]
2 years ago
9

During a weekend music festival, surveys are taken from a sample size of 40 people on their age. The sample proportion of peop

le in their 40s compared to everyone is found. What is the distribution of the sample proportion?
A.
normal distribution skewed to the right

B.
not a normal distribution

C.
normal distribution

D.
normal distribution skewed to the left
Mathematics
1 answer:
Andreas93 [3]2 years ago
6 0

Answer:

C.  

normal distribution

Step-by-step explanation:

The Sampling Distribution of the Sample Proportion. If repeated random samples of a given size n are taken from a population of values for a categorical variable, where the proportion in the category of interest is p, then the mean of all sample proportions (p-hat) is the population proportion (p)

Sample proportion would be normal with mean = p and variance = pq/n where q = 1-p and n= the sample size

The condition is that both np and nq must be greater than 10

Hence we can take that this will be normal provided np>10 or p>1/4 and q >1/4

i.e. p lies between 1/4 and 3/4

C.  

normal distribution (assuming conditions are satisfied)

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Answer:

a

The Null hypothesis represented as

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The Alternative hypothesis represented as

     H_a: \mu_1 -  \mu_2  <  0

b

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c

There is insufficient evidence to conclude that graduate students score higher, on average, on the HPI than undergraduate students

Step-by-step explanation:

From the question we are told that

   The population size is  n= 650

    The  sample size for graduates is  n_1 =  300

     The sample  mean for graduates is \= x _1 =  148

      The sample  standard deviation for graduates is \sigma_1  =  16

    The  sample size for under-graduates is n _2 = 350

         The sample  mean for under-graduates is \= x _2 =  153

         The sample  standard deviation for graduates is \sigma_2  =  21

The Null hypothesis represented as

     H_0: \mu_1 -  \mu_2  = 0

   

The Alternative hypothesis represented as

     H_a: \mu_1 -  \mu_2  <  0

Where \mu_1 \ and \  \mu_2 are the population mean

  Now the test statistic is mathematically represented as

          t =  \frac{(\= x_1 - \= x_2 ) }{ \sqrt{ \frac{ (n_1 - 1 )\sigma_1 ^2 + (n_2 - 1)\sigma_2^2}{n_1 +n_2 -2} }  * \sqrt{ \frac{1}{n_1}  + \frac{1}{n_2} } }

substituting values

       t =  \frac{(148 - 153 ) }{ \sqrt{ \frac{ (300- 1 )16 ^2 + (350 - 1) 21^2}{300 +350 -2} }  * \sqrt{ \frac{1}{300}  + \frac{1}{350} } }

      t = -3.37

The p-values is mathematically evaluated as

     p-value =  P(Z <  -3.37  )  = 0.000376

The above answer is gotten using a p-value calculator  at (0.05) level of significance

     Looking the p-value we see that it is less than the level of significance (0.05)  so Null hypothesis is rejected

Hence there is insufficient evidence to conclude that graduate students score higher, on average, on the HPI than undergraduate students

   

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4065323 × 10 to the senventh power?
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Answer:

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Step-by-step explanation:

Given data

n1= 60 ; n2 = 100

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