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Bas_tet [7]
3 years ago
9

Need help with stats!

Mathematics
1 answer:
KIM [24]3 years ago
8 0

Answer:

A. a) 24

A. b) 4

B. a) 40320

B. b) 576

Step-by-step explanation:

General formula for Permutations:

P(n,r) = \frac{n!}{(n - r)!}

A. Concert seats:  2 couple --- total of 4 persons.

a) without restrictions

Since there are no restrictions, but that the order is important (John, Mary, Paul, Michelle isn't the  same as Michelle, Mary, Paul, John), it's a permutation calculation.

Then we calculate the permutations of 4, out of 4, so...

P(4,4) = \frac{4!}{(4 - 4)!} = 4! = 24

24 different ways for them to sit.

b) couples together

Now, we can see the problem as having 2 levels of permutations, first the couples, then inside the couples.

There are 2 ways for the first level or order... couples AB or BA, so 2 possibilities.

Inside each couple, man then woman (MW) or woman then man (WM), so 2 possibilities there too on 2nd level.

Overall 2 * 2 = 4 ways to sit by couple.

B) Single file

a) without restrictions

Again, order is important, so another permutation, not a combination.  And since we have no restriction, it can be any sequence.

We then have to calculate the number of permutations of 8 out of 8...

P(8,8) = \frac{8!}{(8 - 8)!} = 8! = 40320

There are 40,320 ways these 8 kids can pass the door.

b) girls first.

So, the four girls have to enter first.... and these four girls can be in any order.. how many permutations? P(4,4)... so 24 as calculated above.

For the four boys, how many permutations?  Yes, again P(4,4)... so 24 again.

Overall, we need to multiply the two... 24 x 24 = 576 ways if the girls enter first, followed by the boys.

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\sqrt{65}

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Answer:

a

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    The decision rule is  

Reject the null hypothesis

e

There is sufficient evidence to support the researchers claim

Step-by-step explanation:

From the question we are told that

 The first sample size is  n_1 = 30

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The null hypothesis is  H_o :  \sigma^2_1 = \sigma^2 _2

The alternative hypothesis is H_a :  \sigma_1 ^2 > \sigma^2_2

Generally from the F statistics table  the critical value of \alpha = 0.05 at first and  second degree of freedom df_1 = n_1 - 1 = 30 - 1 = 29 and  df_2 = n_2 - 1 = 30 - 1 = 29 is  

         F_{critical} = 1.8608

Generally the test statistics is mathematically represented as

       F = \frac{s_1^2 }{s_2^2}

=>   F = \frac{8324 }{2862}

=>   F = 2.9085

Generally from the value obtained we see that  F >  F_{critical } Hence

   The decision rule is  

Reject the null hypothesis

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  There is sufficient evidence to support the researchers claim

   

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The "number" is divided by 4, so we'll just put x/4 as our second term.

   8 + \frac{x}{4}

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