All categories

3 years ago

When multiplying two negative numbers, what kind of number does one always get for an answer?

Mathematics

2 answers:

kvasek [131]3 years ago

4 0

When we multiply two negative numbers, one always gets a positive number.

(-)×(-)= +

Hope it helps

zimovet [89]3 years ago

4 0

Answer:

Step-by-step explana số âm nhan số âm = số dương vd -1.-2=2 :

You might be interested in

Find the value of x

ycow [4]

Answer:

x = 20

Step-by-step explanation:

Each side would be 60. 60/3 would be 20. So x = 20

8 0

3 years ago

Read 2 more answers

in a certain population, 11% of people are left-handed. Suppose that you plan to randomly select 100 people and ask each person

Assoli18 [71]

Answer:

c. A and C

Step-by-step explanation:

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Let X the random variable of interest, on this case we now that:

$X \sim Binom(n=100, p=0.11)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

We need to check the conditions in order to use the normal approximation.

$np=100*0.11=11 > 10 \geq 10$

$n(1-p)=100*(1-0.11)=99 \geq 10$

So we see that we satisfy the conditions and then we can apply the approximation.

If we appply the approximation the new mean and standard deviation are:

$E(X)=np=100*0.11=11$

$\sigma=\sqrt{np(1-p)}=\sqrt{100*0.11(1-0.11)}=3.129$

Part A

We want this probability:

$P(X \geq 12) = 1-P(X$

The z score is defined as

$Z=\frac{x-\mu}{\sigma}$ .

$P(X \geq 12) = 1-P(X$

Part B

P(X>12) = 1-P(X\leq 12) = 1-P(Z< \frac{12-11}{3.129})=1-0.625=0.375[/tex]

Part C

$P(10\leq X \leq 14) = P(X$

The z score is defined as

$Z=\frac{x-\mu}{\sigma}$ .

$P(10 \leq X \leq 14) =P(Z< \frac{14-11}{3.129}) -P(Z< \frac{10-11}{3.129})=P(Z$

So then the best option is : c. A and C

8 0

4 years ago

What's the sum of 28

dybincka [34]

Answer:

14+14=28

14x2=28

4 0

3 years ago

Read 2 more answers

Each day a commuter takes a bus to work, the transportation system has a phone app that tells her what time the bus will arrive.

Paraphin [41]

Answer:

Step-by-step explanation:

Hello!

The commuter is interested in testing if the arrival time showed in the phone app is the same, or similar to the arrival time in real life.

For this, she piked 24 random times for 6 weeks and measured the difference between the actual arrival time and the app estimated time.

The established variable has a normal distribution with a standard deviation of σ= 2 min.

From the taken sample an average time difference of X[bar]= 0.77 was obtained.

If the app is correct, the true mean should be around cero, symbolically: μ=0

a. The hypotheses are:

H₀:μ=0

H₁:μ≠0

b. This test is a one-sample test for the population mean. To be able to do it you need the study variable to be at least normal. It is informed in the test that the population is normal, so the variable "difference between actual arrival time and estimated arrival time" has a normal distribution and the population variance is known, so you can conduct the test using the standard normal distribution.

$Z_{H_0}= \frac{X[bar]-Mu}{\frac{Sigma}{\sqrt{n} } }$