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blondinia [14]
4 years ago
10

The standard deviation of the lifetime of a particular brand of car battery is 4.3 months. A random sample of 10 of these batter

ies is taken. Assuming that the lifetimes of all batteries of this brand are normally distributed, what is the probability that the mean lifetime for this sample is within 1 mouth of the mean lifetime for all batteries of this brand?
a. 0.019
b. 0.184
c. 0.519
d. 0.538
e. 0.769
Mathematics
1 answer:
Anuta_ua [19.1K]4 years ago
7 0

Answer:

d. 0.538

Step-by-step explanation:

Given information.

Standard deviation is 4.3

Random sample of 10

Consider the following calculations

P (sample mean is within 1 month of population mean)=

P(-1*sqrt(10)/4.3 <Z<sqrt(10)/4.3)=P(-.735<Z<0.735)

=0.538

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Answer:There are 72 heads (chicken and rabbit) and 200 legs. How many chickens and rabbits are present totally?

Step-by-step explanation

There are 72 heads (chicken and rabbit) and 200 legs. How many chickens and rabbits are present totally?

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Legs of a rabbit = 4

Total heads = 72

Total legs= 200

Let's assume that each of them has minimum 2 legs.

So 72*2 = 144 legs

Remaining legs: 200-144= 56

These remaining legs belong to rabbit because rabbit has 4 legs each.

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Rabbits= 56/2 = 28

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Step-by-step explanation:

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The line of best fit is a straight line representing the regression equation on a scatter plot. The may pass through either some point or all points or none of the points.

<u>Method 1:</u>

Using regression analysis the line of best fit is: y=\alpha +\beta x+e

Here <em>α </em>= intercept, <em>β</em> = slope and <em>e</em> = error.

The formula to compute the intercept is:

\alpha =\bar y-\beta \bar x

Here<em> </em>\bar y and \bar x are mean of the <em>y</em> and <em>x</em> values respectively.

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\beta =\frac{\sum (x-\bar x)(y - \bar y)}{\sum (x=\bar x)^{2}}

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<u>Method 2:</u>

The regression line can be determined using the descriptive statistics mean, standard deviation and correlation.

The equation of the line of best fit is:

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