Please help 50 points to whoever answers, and brainliest to best answer!!!!

A sample of students from an introductory psychology class were polled regarding the number of hours they spent studying for the

Anni [7]

Answer:

$8.68,13.16$

Step-by-step explanation:

Hint- First we have to calculate the mean and standard deviation of the sample and then applying formula for confidence interval we can get the values.

Mean of the sample is,

$\mu=\dfrac{\sum _{i=1}^{24}a_i}{24}=\dfrac{262}{24}=10.92$

Standard deviation of the sample is,

$\sigma =\sqrt{\dfrac{\sum _{i=1}^{24}\left(x_i-10.92\right)^2}{24-1}}=5.6$

The confidence interval will be,

$=\mu \pm Z\dfrac{\sigma}{\sqrt{n}}$

Here,

Z for 95% confidence interval is 1.96, and n is sample size which is 24.

Putting the values,

$=10.92 \pm 1.96\cdot \dfrac{5.6}{\sqrt{24}}$

$=10.92 \pm 2.24$

$=8.68,13.16$

Confidence interval is used to express the degree of uncertainty associated with a sample.

95% confidence interval means that if we used the same sampling method to select different samples and calculate an interval, we would expect the true population parameter to fall within the interval for 95% of the time.

5 0

2 years ago

Malcom is filling bags with rice . He starts with a 5 1/4 pound container of rice and fills each bag with 5/8 pounds of rice . H

timama [110]

Answer:

Malcolm would fill 8 bags of rice.

Step-by-step explanation:

The size of the container of rice = 5 $\frac{1}{4}$ pounds = $\frac{21}{4}$ pounds.

Each bag of rice has a capacity of $\frac{5}{8}$ pounds.

The number of bags of rice that Malcolm fills = $\frac{total quantity of rice}{capacity of each bag}$

= $\frac{21}{4}$ ÷ $\frac{5}{8}$

= $\frac{21}{4}$ x $\frac{8}{5}$

= $\frac{42}{5}$

= 8 $\frac{2}{5}$

Therefore, Malcolm would be able to fill 8 bags of rice.

6 0

3 years ago

Find the circumference of the circle. Round to the nearest tenth if necessary.

NikAS [45]

Answer:

c.132

Step-by-step explanation:

so we are given the diameter which is 42m **the diameter is the straight line that passes through the middle of the circle**

but in order to find the circumference we need to find the radius **the radius is always half (1/2,0.5) of the diameter**

so we have to divide 42/2 which equals 21

now we need to set up the formula;

c=2πr/c=2xπxr **when unknown variables such as 'r' are next to another mathematical numeral such as the pi symbol you don't really have to but the multiplication symbol between them**

c=2π21

=131.946891451

and in your case, it seems we must round to the tenths place so the nine then "becomes a ten" and you're left with 132

good luck :)

i hope this helps

have a good one !!

6 0

2 years ago

A bouncy ball is dropped such that the height of its first bounce is 5.5 feet and each successive bounce is 64% of the previous

ahrayia [7]

Answer:

0.4 ft

Step-by-step explanation:

It can be convenient to let a spreadsheet compute the values for you. Here, we have written an explicit formula for the height of the n-th bounce:

h = 5.5×0.64^(n-1)

We have written the formula this way because we are given the height of the first bounce, not the starting height. Each bounce multiplies the height by a factor of 0.64. Then the 7th bounce will have a height of ...

h = 5.5×0.64^6 ≈ 0.378 ≈ 0.4 . . . . feet

6 0

3 years ago

Gina wants to take dance classes. She compares two dance studios to determine which has the best deal for her. Dance World charg

fomenos

Answer:

10 classes

Step-by-step explanation:

Given equations in the question

Dance World: y = 15x

Toe Tappers: y = 25 + 12.5x

Where,

x = number of classes

Equate the total cost at both dance studios

15x = 25 + 12.5x

Collect like terms

15x - 12.5x = 25

2.5x = 25

Divide both sides by 2.5

2.5x / 2.5 = 25 / 2.5

x = 10 classes

x = number of classes = 10

4 0

2 years ago