The gypsy moth is a serious threat to oak and aspen trees. A state agriculture department places traps throughout the state to detect the moths. When traps are checked periodically, the mean number of moths trapped is only 0.7, but some traps have several moths. The distribution of moth counts is discrete and strongly skewed, with standard deviation 0.8.
A) What are the mean and standard deviation of the average number of moths x in 60 traps?
B) Use the central limit theorem to find the probability (±0.01) that the average number of moths in 40 traps is greater than 0.4.

Answer:

a) The insurance should be of 84.6 months, that is, approximately 85 months.

b) 0.0436 = 4.36% probability that it will malfunction before the insurance coverage ends.

c) The expected loss to the insurance company is of 2.18 million.

d) The company should expect to make a profit of $689,200.

Step-by-step explanation:

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

A relay microchip in a telecommunications satellite has a life expectancy that follows a normal distribution with a mean of 90 months and a standard deviation of 3.5 months.

This means that [tex]\mu = 90, \sigma = 3.5[/tex]

A. For how many months should the satellite be insured to be 94% confident that it will last beyond the insurance date?

The 100 - 94 = 6th percentile, which is X when Z has a pvalue of 0.06. So X when Z = -1.555.

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]-1.555 = \frac{X - 90}{3.5}[/tex]

[tex]X - 90 = -1.555*3.5[/tex]

[tex]X = 84.6[/tex]

The insurance should be of 84.6 months, that is, approximately 85 months.

B. If the satellite is insured for 84 months, what is the probability that it will malfunction before the insurance coverage ends?

This is the pvalue of Z when X = 84. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z= \frac{84 - 90}{3.5}[/tex]

[tex]Z = -1.71[/tex]

[tex]Z = -1.71[/tex] has a pvalue of 0.0436

0.0436 = 4.36% probability that it will malfunction before the insurance coverage ends.

C. If the satellite is insured for 84 months, what is the expected loss to the insurance company?

0.0436 probability of losing 50 million. So

0.0436*50 = 2.18

The expected loss to the insurance company is of 2.18 million.

D. If the insurance company charges $3 million for 84 months of insurance, how much profit does the company expect to make?

1 - 0.0436 = 0.9564 probability of making 3 million.

0.0436 probability of losing 50 million

So

[tex]E = 0.9564*3 - 0.0436*50 = 0.6892[/tex]

The company should expect to make a profit of 0.6892 million, that is, $689,200.

Answer: 53

Step-by-step explanation:

Hope this helps!

Answer:

10% or 5%

Step-by-step explanation:

Answer:

The is A) 91

Step-by-step explanation:

Answer:

61

Step-by-step explanation:

2w + 43 = ?, w = 9

Answer:

[tex] {x}^{2} + 2xy + {y}^{2} [/tex]

Step-by-step explanation:

1) Use square sum: (a + b)² = a² + 2ab + b².

[tex] {x}^{2} + 2xy + y^{2} [/tex]

Therefor, the answer is x² + 2xy + y².

Answer:

d metamorphosis

Step-by-step explanation:

Answer:

5150

Step-by-step explanation:

:)

Answer:   1. 29/8

                2. 37.72

                3. 24

Step-by-step explanation:

1. x + 1 3/8 = 2 1/4

              x = 21/4 - 13/8

              x = 42/8 - 13/8           [set the denominator equal]

              x = 29/8

2. 13.27 = t - 24.45

Rewrite the function as t - 24.45 = 13.27

                                                   t  = 13.27 + 24.45

                                                   t  = 37.72              

3.  9 = 3/8 × y

Rewrite as 3/8 x y = 9

                            y = 9/ (3/8)

                            y = 9 x (8/3)

                            y = 24

Answer:

[tex]3a + b = 14[/tex]

[tex]b = 4a[/tex]

Step-by-step explanation:

Key:

a = 3 point throws

b = Free throws

Total points = 14

Required

Determine the system of equations

[tex]Total\ points = 14[/tex] implies that:

[tex]3 * a + b = 14[/tex]

[tex]3a + b = 14[/tex]

4 times as many b as a implies that:

[tex]b = 4 * a[/tex]

[tex]b = 4a[/tex]

So, the system of equations are:

[tex]3a + b = 14[/tex]

[tex]b = 4a[/tex]

just here for the points :l

Answer:

for first one

√8²+4²=24

6²=36 not right angled triangle

so it is obtuse TRAINGLE

Step-by-step explanation:

for second one

it is acute TRAINGLE

Answer:

it will be D i seen this before

Step-by-step explanation:

Answer:

x=2 and y=6

Step-by-step explanation:

Answer:

Right square pyramid

Volume:

Surface area:

Answer:

Enter date and time information at "From:"

Select a month and a day. Enter a year.

The year entered must be a positive number. Not zero (0).

Enter hours and minutes. Select am or pm.

The hours entered must be a positive number between 1 and 12 or zero (0).

The minutes entered must be a positive number between 1 and 59 or zero (0).

Add or Subtract Line

Enter number of days, hours and minutes

Select "add" or "subtract"

If you type "ghblxz", in the year box the computer will print "0"

If you type "1.9e2", the computer will use "190" to calculate the answer.

If you select "February 31", the computer will print "Not a Day"

Click "Click to Calculate" button. The calculated date and time will appear.

NaN = not a number

To clear the entry boxes click "Reset

Answer:

150000000000

Step-by-step explanation:

1.5x10¹¹

= 150000000000

You can think about scientific notations by moving the position of the 'dot' 11 times to the right

Answer:

1/3

i don't know laughing out loud

Answer:

6^7

Step-by-step explanation:

6^8 x 6^-1

6^{8-1}

6^7

Answer:

2,000 meters

Step-by-step explanation:

I multiplied 100 by 20.

Hope this helped

each minute, they swim 50 m.

20*50 = 1000

Answer:

The maximum error in the calculated surface area is approximately 8.3083 square centimeters.

Step-by-step explanation:

The circumference ([tex]s[/tex]), in centimeters, and the surface area ([tex]A_{s}[/tex]), in square centimeters, of a sphere are represented by following formulas:

[tex]A_{s} = 4\pi\cdot r^{2}[/tex] (1)

[tex]s = 2\pi\cdot r[/tex] (2)

Where [tex]r[/tex] is the radius of the sphere, in centimeters.

By applying (2) in (1), we derive this expression:

[tex]A_{s} = 4\pi\cdot \left(\frac{s}{2\pi} \right)^{2}[/tex]

[tex]A_{s} = \frac{s^{2}}{\pi^{2}}[/tex] (3)

By definition of Total Differential, which is equivalent to definition of Linear Approximation in this case, we determine an expression for the maximum error in the calculated surface area ([tex]\Delta A_{s}[/tex]), in square centimeters:

[tex]\Delta A_{s} = \frac{\partial A_{s}}{\partial s} \cdot \Delta s[/tex]

[tex]\Delta A_{s} = \frac{2\cdot s\cdot \Delta s}{\pi^{2}}[/tex] (4)

Where:

[tex]s[/tex] - Measure circumference, in centimeters.

[tex]\Delta s[/tex] - Possible error in circumference, in centimeters.

If we know that [tex]s = 82\,cm[/tex] and [tex]\Delta s = 0.5\,cm[/tex], then the maximum error is:

[tex]\Delta A_{s} \approx 8.3083\,cm^{2}[/tex]

The maximum error in the calculated surface area is approximately 8.3083 square centimeters.

Answer:

$82.50

Step-by-step explanation:

Answer:

10(7q + 6)

Step-by-step explanation:

I hope this helps!

Answer:

540 feet

Step-by-step explanation:

[tex]\frac{36}{100} = \frac{x}{1500}[/tex]  Cross multipy

100x = 54000

54000/100 = 540

x = 540

Answer:

area is approximately 36.56

Step-by-step explanation: