All categories

3 years ago

I need help with number 2 and 4 Someone please help

Mathematics

2 answers:

geniusboy [140]3 years ago

8 0

1.defined
2.undefined
defined coz its a pencil
2 cause its a raindrop which is straight

Sophie [7]3 years ago

5 0

2.unidentified and 4.identified

You might be interested in

. Carlos and his family left for the amusement park at 7:35a.M. The trip took 1 hour 45 minutes. What time did they arrive?

Alex

Answer:

they arrived at 9:20 A.M.

Step-by-step explanation:

If you look at the time they left and how much time it took for them to arrive all you have to do is add 1:45 to 7:35 while adding in time sense so add the 5 to 35 to get 7:40 then add 20 from the 40 to the other 40 to get 8:00 then you can add the remaining 20 to get 8:20 now you can add the hour to make it 9:20 A.M.

6 0

3 years ago

Read 2 more answers

Swad attempted 56 free throws during the basketball season. He made

torisob [31]

Answer:

Step-by-step explanation:

8 0

3 years ago

The average life of a bread-making machine is 7 years, with a standard deviation of 1 year. Assuming that the lives of these mac

Alina [70]

Answer:

a) $P(6.4$

b) $a=7 +1.036*0.333=7.345$

So the value of bread-making machine that separates the bottom 85% of data from the top 15% is 7.345.

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".

Let X the random variable life of a bread making machine. We know from the problem that the distribution for the random variable X is given by:

$X\sim N(\mu =7,\sigma =1)$

We take a sample of n=9 . That represent the sample size.

From the central limit theorem we know that the distribution for the sample mean $\bar X$ is also normal and is given by:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

$\bar X \sim N(\mu=7, \frac{1}{\sqrt{9}})$

Solution to the problem

Part a

(a) the probability that the mean life of a random sample of 9 such machines falls between 6.4 and 7.2

In order to answer this question we can use the z score in order to find the probabilities, the formula given by:

$z=\frac{\bar X- \mu}{\frac{\sigma}{\sqrt{n}}}$

The standard error is given by this formula:

$Se=\frac{\sigma}{\sqrt{n}}=\frac{1}{\sqrt{9}}=0.333$

We want this probability:

$P(6.4$

Part b

b) The value of x to the right of which 15% of the means computed from random samples of size 9 would fall.

For this part we want to find a value a, such that we satisfy this condition:

$P(\bar X>a)=0.15$ (a)

$P(\bar X$ (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.85 of the area on the left and 0.15 of the area on the right it's z=1.036. On this case P(Z<1.036)=0.85 and P(Z>1.036)=0.15

If we use condition (b) from previous we have this:

$P(X$