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A chef knows it will take two hours and fifteen minutes to prepare and cook a lunch. He starts preparing the lunch at a quarter

beks73 [17]

Well simply minus fifteen minutes for each qauter

7 0

3 years ago

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The ideal (daytime) noise-level for hospitals is 45 decibels with a standard deviation of 10 db; which is to say, this may not b

WINSTONCH [101]

Answer:

(a) A 99% confidence interval for the actual mean noise level in hospitals is (44.02 db, 49.98 db).

(b) We can be 90% confident that the actual mean noise level in hospitals is 47 db with a margin of error of 1.89 db.

(c) Unless our sample (of 81 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between 44.41 db and 49.59 db.

Step-by-step explanation:

The problem is incomplete. The questions are:

(a) A 99% confidence interval for the actual mean noise level in hospitals is (44.02 db, 49.98 db).

For a 99% CI, the value of z is z=2.58

Then, the confidence interval for the mean is:

$M-z\sigma/\sqrt{n}\leq\mu\leq M-z\sigma/\sqrt{n}\\\\47-2.58*10/\sqrt{75} \leq\mu\leq47+2.58*10/\sqrt{75}\\\\47-2.98\leq\mu\leq47+2.98\\\\44.02\leq\mu\leq 49.98$

(b) We can be 90% confident that the actual mean noise level in hospitals is 47 db with a margin of error of 1.89 db.

For a 90% CI, the value of z is z=1.64.

Then, we can calculate the margin of error as:

$E=z*\sigma/\sqrt{n}=1.64*10/\sqrt{75}=1.89$

(c) Unless our sample (of 81 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between 44.41 db and 49.59 db.

The 2% tails data corresponds, in the standard normal distirbution, to the values of z whose absolute value is higher than 2.33.

The values of db for these critical values are:

$X_1=M+z_1*\sigma/\sqrt{n}=47+(-2.33)*10/\sqrt{81}=47-2.59=44.41\\\\\\ X_2=M+z_2*\sigma/\sqrt{n}=47+(2.33)*10/\sqrt{81}=47+2.59=49.59$

3 0

3 years ago

The triangle shown below has an area of 40 units”. Find the missing side.

Margarita [4]

Answer:

the answer is 10

Step-by-step explanation:

Because the formula for area of a triangle is b x h/2 so you would 8 *10 which would be 80 then you would divide 80 by two and then you would get your answer

8 0

3 years ago

Need help asap please

Pepsi [2]

Step-by-step explanation:

first of all, your teacher wrote nonsense in the answer options : an area is always given in squared units. never in cubed units (which would be volume).

the area is : 1/2 × perimeter × apothem

the perimeter is simply 12 × 5 = 60 meters.

apothem = (a/2)×cot(pi/12) = 5/2 × cot(pi/12) =

= 9.330127019... meters

so the area is

1/2 × 60 × 9.330127019... = 279.9038106... m²

therefore, the third answer option is correct (although it is m², and not m³).

by the way, you have question 3 wrong. I answered this with the correct apothem calculation in the explanation for question 4.

5 0

1 year ago

Find the unit rate $72 in 4 hours

shepuryov [24]

Answer:

72 dollars ÷ 4

4 hours ÷ 4

=

18 dollars

1 hour

=

18 dollars

hour

= 18 dollars per hour

Step-by-step explanation:

7 0

3 years ago

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