Simplifying Square root of -100

alekssr [168]

D is the ans. Square root of 49 equals to 7

8 0

3 years ago

Suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000. use the 68-95-99.7 rule to

Novosadov [1.4K]

Answer:

We want to find the percentage of values between 147700 and 152300

$P(147700$

And one way to solve this is use a formula called z score in order to find the number of deviations from the mean for the limits given:

$z= \frac{x-\mu}{\sigma}$

And replacing we got:

$z=\frac{147700-150000}{2300}=-1$

$z=\frac{152300-150000}{2300}=1$

So then we are within 1 deviation from the mean so then we can conclude that the percentage of values between $147,700 and $152,300 is 68%

Step-by-step explanation:

We define the random variable representing the prices of a certain model as X and the distirbution for this random variable is given by:

$X \sim N(\mu = 150000, \sigma =2300$

The empirical rule states that within one deviation from the mean we have 68% of the data, within 2 deviations from the mean we have 95% and within 3 deviations 99.7 % of the data.

We want to find the percentage of values between 147700 and 152300

$P(147700$

And one way to solve this is use a formula called z score in order to find the number of deviations from the mean for the limits given:

$z= \frac{x-\mu}{\sigma}$

And replacing we got:

$z=\frac{147700-150000}{2300}=-1$

$z=\frac{152300-150000}{2300}=1$

So then we are within 1 deviation from the mean so then we can conclude that the percentage of values between $147,700 and $152,300 is 68%

7 0

3 years ago

A research scientist wants to know how many times per hour a certain strand of bacteria reproduces. He wants to construct the 95

Galina-37 [17]

Answer:

The minimum sample size required for the estimate is 345.

Step-by-step explanation:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

The standard deviation is known to be 1.8.

This means that $\sigma = 1.8$

What is the minimum sample size required for the estimate?

This is n for which M = 0.19. So

$M = z\frac{\sigma}{\sqrt{n}}$

$0.19 = 1.96\frac{1.8}{\sqrt{n}}$

$0.19\sqrt{n} = 1.96*1.8$

$\sqrt{n} = \frac{1.96*1.8}{0.19}$

$(\sqrt{n})^2 = (\frac{1.96*1.8}{0.19})^2$

$n = 344.8$

Rounding up to the next integer:

The minimum sample size required for the estimate is 345.

8 0

3 years ago

Rocco runs diagonally across a square field.

valkas [14]

Rocco would have to run diagonally 27 times

7 0

3 years ago

Suppose you have a group of 8 male and 4 female volunteers. how many ways are there to choose 6 of these volunteers for a treatm

Kay [80]

Since volunteers can be of any sexe (no precision given in your problem), then we can consider the question as how many group of 6 we can make with 12 persons:
It's a combination of 6 chosen among 12

¹²C₆ = (12!)/(6!).(12-6!)

²C₆ = (12!)/(6!).(6!)<span>

</span>¹²C<span>₆</span> = 924 Ways

6 0

4 years ago