2/3=? 5/4=? 24/4=?<br><br> Help me with this

Can someone help me with this?

Mariulka [41]

Answer:

1) $4+5=9$ .

2) $2+(-6)=-4$

3) $-3+(-7)=-10$

4) $(-7)+3=-4$

5) $9+(-4)=5$

6) $-1+4=3$

7) $5+(-5)=0$

8) $-3+(-6)=-9$

Step-by-step explanation:

In the given number lines, rightarrows represent positive integers and leftarrows represent negative integers.

1)

In first number line we have two rightarrows.

Rightarrow from 0-4 = 4

Rightarrow from 4-9 = 5

So, required sum is $4+5=9$ .

Similarly,

2)

$2+(-6)=-4$

3)

$-3+(-7)=-10$

4)

$(-7)+3=-4$

5)

$9+(-4)=5$

6)

$-1+4=3$

7)

$5+(-5)=0$

8)

$-3+(-6)=-9$

8 0

3 years ago

What is an example of when you would want consistent data and, therefore, a small standard deviation?

steposvetlana [31]

Answer:

12.1, 12.3,12.4,12.5,12.3,12.1,12.2

$\bar X= \frac{12.1+12.3+12.4+12.5+12.3+12.1+12.2}{7}=12.271$

And for the standard deviation we can use the following formula:

$s= \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And after replace we got:

$s = 0.1496$

And as we can ee we got a small value for the deviation <1 on this case.

Step-by-step explanation:

For example if we have the following data:

12.1, 12.3,12.4,12.5,12.3,12.1,12.2

We see that the data are similar for all the observations so we would expect a small standard deviation

If we calculate the sample mean we can use the following formula:

$\bar X=\frac{\sum_{i=1}^n X_i}{n}$

And replacing we got:

$\bar X= \frac{12.1+12.3+12.4+12.5+12.3+12.1+12.2}{7}=12.271$

And for the standard deviation we can use the following formula:

$s= \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}$

And after replace we got:

$s = 0.1496$

And as we can ee we got a small value for the deviation <1 on this case.

8 0

3 years ago

What is the answer 5i/(2+3i)^2

Nataly_w [17]

Simplify the following:5 i/(3 i + 2)^2
(3 i + 2)^2 = 4 + 6 i + 6 i - 9 = -5 + 12 i:(5 i)/12 i - 5
Multiply numerator and denominator of (5 i)/(12 i - 5) by 5 + 12 i:(5 i (12 i + 5))/((12 i - 5) (12 i + 5))
(12 i - 5) (12 i + 5) = -5×5 - 5×12 i + 12 i×5 + 12 i×12 i = -25 - 60 i + 60 i - 144 = -169:(5 i (12 i + 5))/-169
i (12 i + 5) = -12 + 5 i:(5 5 i - 12)/(-169)
Multiply numerator and denominator of (5 (5 i - 12))/(-169) by -1:Answer: (-5 (5 i - 12))/169

3 0

3 years ago

According to a report from a business intelligence company, smartphone owners are using an average of 22 apps per month. Assume

Ira Lisetskai [31]

Answer:

0.4332 = 43.32% probability that the sample mean is between 21 and 22.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .