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2 years ago

Thanks for your help

Mathematics

1 answer:

vampirchik [111]2 years ago

5 0

The answer would be b=4.2

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A statistics teacher started class one day by drawing the names of 10 students out of a hat and asked them to do as many pushups

HACTEHA [7]

Answer: b. 8.56 to 21.44

Step-by-step explanation:

Let $\mu$ be the mean number of pushups that can be done.

As per given , we have

Sample size : n= 10

Degree of freedom = n-1=9

Sample mean : $\overline{x}=15$

Sample standard deviation : $s=9$

Significance level : α=1-0.95=0.05

From t- distribution table ,

Critical two -tailed t-value for α=0.05 and df = 9 is

$t_{\alpha/2, 9}=t_{0.025,9}=2.2622$

Confidence interval for $\mu$ is given by :-

$\overline{x}\pm t*\dfrac{s}{\sqrt{n}}$

$=15\pm (2.2622)\dfrac{9}{\sqrt{10}}\\\\\approx 15\pm 6.44=(15-6.44,\ 15+6.44)\\\\=(8.56,\ 21.44)$

Hence, the 95% confidence interval for the true mean number of pushups that can be done is 8.56 to 21.44.

5 0

2 years ago

Please help me i rlly need help lol i have to written

MissTica

Take the picture clearly because I can’t read nothing

6 0

2 years ago

"the life length x (in years) of a dvd player" is exponentially distributed with mean 5 years. what is the probability that a mo

loris [4]

The exponential distribution is:
$\lambda e^{- \lambda x}$
where $\lambda = \frac{1}{mean}=\frac{1}{5}$

The probability we want is how likely will a dvd player last more than 8 years, given it has already lasted 5 years
To find this, you use conditional probability.
$P(A|B) = \frac{P(A and B)}{P(B)}$
where A is P(x>8) and B is P(x>5)
To find these probabilities, integrate over the distribution:
$P(x \ \textgreater \ N) = \int_N^{\infty} \frac{1}{5} e^{-x/5} dx = e^{-N/5}$

Sub into conditional probability formula:

$P(x \ \textgreater \ 8 | x\ \textgreater \ 5) = \frac{P(x\ \textgreater \ 8)}{P(x\ \textgreater \ 5)} = \frac{e^{-8/5}}{e^{-5/5}} = e^{-3/5} = 0.549$

Final Answer: Given a dvd player is more than 5 years old, the probability that it will last another 3 more years is about 54.9%

3 0

3 years ago

How can you explain the answer 4 divided by 5

Sergio [31]

Answer:

4 divided by 5 is equal to 0.8. This decimal can also be written as a fraction. 0.8 = eight tenths or 8/10 (4/5 in its reduced form).

Step-by-step explanation:

3 0

2 years ago

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How do you put the equation 2x+y=2 into slope intercept form

Dahasolnce [82]