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3 years ago

I need to know the minutes before the hour

Mathematics

2 answers:

steposvetlana [31]3 years ago

6 0

The answer is it is 7 minutes before 8:00 a.m.

Lesechka [4]3 years ago

6 0

Answer: I can’t see the picture really well

Step-by-step explanation:

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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:

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

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4 years ago

What is the value of i 20+1

zmey [24]

Answer:

<h2>21 no sure what the "i" means</h2>

Step-by-step explanation:

6 0

3 years ago

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Water is added or drained from a tank each day. The first day, 9/10 of a gallon is added to the empty tank. The second day, 7/10

lorasvet [3.4K]

Answer:

Step-by-step explanation:

9/10+(−7/10)+8/10+(−6/10)+3/10+(−1/10)+2/10.

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2 years ago

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Determine whether the samples are independent or dependent. Upper A data set includes the weight of 140 students before and afte

Serhud [2]

Answer:

Option C)

Step-by-step explanation:

The samples are dependant. There should be a relation between the weights of the students, even though there could be changes, as any value can go up or down. A student with a weight around of 30 has a higher chance of getting a weight around of 35 after the firts year than a student with weight around of 55. This means that the probability a student has for getting certain amount of weight after the first year may change depending on the weight the student had at the start of the year. You can therefore naturally relate the weight a student had before the first year with the weight the student had after the first year.

So, the samples are dependant because there is a natural pairing between the to samples, as option C says.

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3 years ago

What percent of 125 is 60?

Diano4ka-milaya [45]

Answer:

48%

Step-by-step explanation:

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3 years ago

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I need to know the minutes before the hour​

I need to know the minutes before the hour