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3 years ago

Solve: -2 1/3-(-5)= what Please help

Mathematics

1 answer:

OLEGan [10]3 years ago

7 0

Answer:

8/3

Step-by-step explanation:

$\frac{ - 7}{3} + 5 = \frac{8}{3}$

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One of your peers claims that boys do better in math classes than girls. Together you run two independent simple random samples

JulijaS [17]

Answer:

Step-by-step explanation:

Hello!

To test if boys are better in math classes than girls two random samples were taken:

Sample 1

X₁: score of a boy in calculus

n₁= 15

X[bar]₁= 82.3%

S₁= 5.6%

Sample 2

X₂: Score in the calculus of a girl

n₂= 12

X[bar]₂= 81.2%

S₂= 6.7%

To estimate per CI the difference between the mean percentage that boys obtained in calculus and the mean percentage that girls obtained in calculus, you need that both variables of interest come from normal populations.

To be able to use a pooled variance t-test you have to also assume that the population variances, although unknown, are equal.

Then you can calculate the interval as:

[(X[bar]_1-X[bar_2) ± $t_{n_1+n_2-2;1-\alpha /2}$ * $Sa*\sqrt{\frac{1}{n_1} +\frac{1}{n_2} }$ ]

$Sa= \sqrt{\frac{(n_1-1)S^2_1+(n_2-1)S^2_2}{n_1+n_2-2} } = \sqrt{\frac{14*(5.6^2)+11*(6.7^2)}{15+12-2} }= 6.108= 6.11$

$t_{n_1+n_2-2;1-\alpha /2}= t_{15+12-2;1-0.05}= t_{25;0.95}= 1.708$

[(82.3-81.2) ± 1.708* (6.11* $\sqrt{\frac{1}{15}+\frac{1}{12} }$ ]

[-2.94; 5.14]

Using a 90% confidence level you'd expect the interval [-2.94; 5.14] to contain the true value of the difference between the average percentage obtained in calculus by boys and the average percentage obtained in calculus by girls.

I hope this helps!

3 0

3 years ago

How many two-digit positive integers can be formed the digits 1,5,6, and 8 if no digit is repeated?

IgorLugansk [536]

Answer:

Step-by-step explanation:

There are 4 different digits to choose from. Since we want 2-digit number, we will see what digits can we put in place of 1st digit and what digit can we place in place of 2nd digit.

Hence, how many digits (from 1,5,6 and 8) can be placed in the 1st digit of the number we want?

Any one of the four digits (1,5,6, or 8).

Now, How many digits (from 1,5,6 and 8) can be placed as the 2nd digit of the number we want?

Any one of the THREE digits (since repetition is not allowed, we disregard the initial digit).

Thus the number of two-digit positive integers is 4 * 3 = 12

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3 years ago

Will give brainlist if its a full answer

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Answer:

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Step-by-step explanation:

you just add the two amounts of soap he put into the container and subtract it from the total amount of soap he had, 2 L.

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3 years ago

A shose box measures 15in.by 7in.by 4 an half

Svet_ta [14]

The volume is 472.5in^3.

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4 years ago

On a necklace of 100 beads, 45 of the beads are round. The rest of the

mina [271]

Answer:

45% round 55% rectangular

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3 years ago

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