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3 years ago

Any smart people want to help me

Mathematics

2 answers:

katrin [286]3 years ago

5 0

Answer:

Step-by-step explanation:

26 students = 15 students + 11 students

135 for 1st 15, 7.50 for rest

135 + 7.50(11) = 217.50

Therefore, B

Alexus [3.1K]3 years ago

3 0

Answer:

$217.50

Step-by-step explanation:

$135 + (11*$7.50) = $217.50

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Helppppp mee plz i neeed help

Butoxors [25]

Answer:

Basically the first image goes in the first box because opposites attract and the second image is what happens when you let the magnets go. The third image would go into the second chart because same-sides repel each other and the fourth picture shows what happens if you let the magnets that have the same sides facing each other go.

Step-by-step explanation:

4 0

3 years ago

A random sample of 64 observations produced a mean value of 84 and standard deviation of 5.5. The 90% confidence interval for th

ASHA 777 [7]

Answer: The 90% confidence interval for the population mean μ is between 82.85 and 85.15,

Step-by-step explanation:

When population standard deviation is not given ,The confidence interval population proportion is given by ( $\mu$ ):-

$\overline{x}\pm t^*\dfrac{s}{\sqrt{n}}$

, where n= Sample size.

s= Sample standard deviation

$\overline{x}$ = sample mean

t* = Critical t-value (Two-tailed)

As per given , we have

$\overline{x}=84$

n= 64

Degree of freedom : df = n-1=63

s= 5.5

Significance level : $\alpha=1-0.90=0.1$

Two-tailed T-value for df = 63 and $\alpha=1-0.90=0.1$ would be

$t_{\alpha/2,df}=t_{0.05,63}=1.669$ (By t-distribution table)

i.e. t*= 1.669

The 90% confidence interval for the population mean μ would be

$84\pm (1.669)\dfrac{5.5}{\sqrt{64}}$

$=84\pm (1.669)\dfrac{5.5}{8}$

$\approx84\pm 1.15$

$=(84-1.15,\ 84+1.15)=(82.85,\ 85.15)$

∴ The 90% confidence interval for the population mean μ is between 82.85 and 85.15,

6 0

3 years ago

aleksandr82 [10.1K]

Answer:

x = 30

Step-by-step explanation:

Since this is a right triangle,

90 = (x + 20) + (x + 10)

90 = x + x + 20 + 10

90 = 2x + 30

90 - 30 = 2x

60 = 2x

60/2 = 2x/2

30 = x

Check:

x + 20

30 + 20 = 50

x + 10

30 + 10 = 40

50 + 40 = 90

Hope this helps!

4 0

2 years ago

First 5 multiples of 25

Anastasy [175]

25 , 50 , 75 , 100 ,125

3 0

3 years ago

Based on aâ poll, among adults who regret gettingâ tattoos, 18â% say that they were too young when they got their tattoos. Assum

Sergeeva-Olga [200]

Answer:

a) 20.44% probability that none of the selected adults say that they were too young to get tattoos.

b) 35.90% probability that exactly one of the selected adults says that he or she was too young to get tattoos.

c) 56.34% probability that the number of selected adults saying they were too young is 0 or 1.

d) No

Step-by-step explanation:

For each adult, there are only two possible outcomes. Either they say they were too young when they got their tattoos, or they don't say that. Each adult is independent of each other. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

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

And p is the probability of X happening.

18% say that they were too young when they got their tattoos.

This means that $p = 0.18$

Eight adults who regret getting tattoos are randomly selected

This means that $n = 8$

a. Find the probability that none of the selected adults say that they were too young to get tattoos.

This is P(X = 0).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{8,0}.(0.18)^{0}.(0.82)^{8} = 0.2044$

20.44% probability that none of the selected adults say that they were too young to get tattoos.

b. Find the probability that exactly one of the selected adults says that he or she was too young to get tattoos.

This is P(X = 1).

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 1) = C_{8,1}.(0.18)^{1}.(0.82)^{7} = 0.3590$

35.90% probability that exactly one of the selected adults says that he or she was too young to get tattoos.

c. Find the probability that the number of selected adults saying they were too young is 0 or 1.

Either a. or b.

20.44 + 35.90 = 56.34

56.34% probability that the number of selected adults saying they were too young is 0 or 1.

d. It we randomly select 9 adults. Is 1 a significantly low number who day that they were too young to get tattoos?

Now $n = 9$

It is significantly low if it is more than 2.5 standard deviations below the mean.

The mean is $E(X) = np = 9*0.18 = 1.62$

The standard deviation is $\sqrt{V(X)} = \sqrt{n*p*(1-p)} = \sqrt{9*0.18*0.82} = 1.15$

1 > (1.62 - 2.5*1.15)

So the answer is no.

5 0

3 years ago