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4 years ago

Is this right?? please help!

Mathematics

1 answer:

Ganezh [65]4 years ago

4 0

Answer:

6 < x < 8

Step-by-step explanation:

The compound inequality in this instance represent the "and" condition, not the "or" condition.* We might solve it like this.

-47 > 1 -8x > -63 . . . . given

Multiply by -1:

47 < -1 +8x < 63

Add 1:

48 < 8x < 64

Divide by 8:

6 < x < 8

______

* You can tell this is the case by looking at the ends of the given statement:

-47 > -63 . . . . a true statement, so the solution set will be an intersection, not a union.

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The heights of 40 randomly chosen men are measured and found to follow a normal distribution. An average height of 175 cm is obt

AVprozaik [17]

Answer:

95% two-sided confidence interval for the true mean heights of men is [168.8 cm , 181.2 cm].

Step-by-step explanation:

We are given that the heights of 40 randomly chosen men are measured and found to follow a normal distribution.

An average height of 175 cm is obtained. The standard deviation of men's heights is 20 cm.

Firstly, the pivotal quantity for 95% confidence interval for the true mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample average height = 175 cm

$\sigma$ = population standard deviation = 20 cm

n = sample of men = 40

Here for constructing 95% confidence interval we have used One-sample z test statistics as we know about population standard deviation.

So, 95% confidence interval for the true mean, $\mu$ is ;

P(-1.96 < N(0,1) < 1.96) = 0.95 {As the critical value of z at 2.5%

level of significance are -1.96 & 1.96}

P(-1.96 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ , $\bar X+1.96 \times }{\frac{\sigma}{\sqrt{n} } }$ ]

= [ $175-1.96 \times }{\frac{20}{\sqrt{40} } }$ , $175+1.96 \times }{\frac{20}{\sqrt{40} } }$ ]

= [168.8 cm , 181.2 cm]

Therefore, 95% confidence interval for the true mean height of men is [168.8 cm , 181.2 cm].

The interpretation of the above interval is that we are 95% confident that the true mean height of men will be between 168.8 cm and 181.2 cm.

3 0

3 years ago

87th term of 12,0,-12

Elan Coil [88]

Answer:

$a_{87} = -1020$

Step-by-step explanation:

Given:

The given AP is.

12,0,-12,......

$n=87$

The first term of an AP $a=12$

Common difference $d=0-12=-12$

We use the the formula for nth term of an AP.

$a_{n} = a+(n-1)d$

for 87th term

$a_{87} = 12+(87-1)(-12)$

$a_{87} = 12+(86)(-12)$

$a_{87} = 12+(-1032)$

$a_{87} = 12-1032$

$a_{87} = -1020$

Therefore, The 87th term of given series is -1020.

5 0

3 years ago

Solve for the variable in the following proportion.

erastovalidia [21]

Answer: b = 10

Step-by-step explanation:

We want a ratio of b/2 that is equal to the ratio of 1/4 to 1 1/4 (or 5/4).

Ratio of (1/4)/(5/4):

(1/4)/(5/4) = (1/4)*(4/5) = 4/20 = 1/5 or 0.2

We want 2/b = 1/5 or 0.20

2/b = 0.20

b = 2/0.20

b = 10

Check: Does 10/2 = (1/4)/(5/4)?

Yes

b is 10

3 0

2 years ago

Helpppppppppp please and thank uuuuuuuu

kari74 [83]

Answer:

U, D, L

Step-by-step explanation:

E: 22 × 1.3 = 28.6, Up.

F: 7.25 × 6.5 = 47.13 (Rounded), Down.

G: 212 × 0.99 = 209.88, Left.

Up, Down, Left = U, D, L

Do you like my drawing? (Although I didn't color it in...)

5 0

3 years ago

On a Saturday, the ratio of the amount of water used by household A to the amount of water use by household B was 13 : 5. Househ

Setler [38]

Step-by-step explanation:

this is my answer I guess this will help

8 0

3 years ago

Read 2 more answers