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3 years ago

What is a placebo and why is it important in an experiment to test the effectiveness of a drug

Mathematics

1 answer:

Sonbull [250]3 years ago

5 0

Answer:

A placebo is a useless substance that takes the place of an actual drug

Step-by-step explanation:

This is to test to see if the drug actually does anything, or if the patients are really just deceived by their imagination

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Ramon is a waiter. He waits on a table of 4 whose bill comes to $99.69. If Ramon receives a 20% tip, approximately how much will

vlabodo [156]

99.69/100=.9969
.9969*20=19.938
Ramon would receive ~ $19.94

4 0

3 years ago

Please help me. this is hard

allochka39001 [22]

Since it is a square that means each side is equal.
The perimeter is 24, and since there is four sides we would divide it by four to find the length of each side.

24/4 = 6

Each side is 6.
By looking at the picture, one side of the square, is the length of the radius.

The radius of the square is 6.

The only thing left to do is to find the circumference.
The circumference formulas are:

C = $\pi$ d
C = 2 $\pi$ r

We can use the first one Diameter x pi (3.14)
To find the diameter we would just multiply the radius by two.

6 x 2 = 12

Diameter = 12

So multiply it by pi

12 x 3.14 = 37.68
or D 12 $\pi$

7 0

3 years ago

As the teams fundraiser,Agnes and Betty both sold candy bars at the end of the fundraiser Agnes determined that she sold 8 more

Romashka-Z-Leto [24]

Answer:

356

Step-by-step explanation:

5 0

3 years ago

A shipment of 50,000 transistors arrives at a manufacturing plant. The quality control engineer at the plant obtains a random sa

Aleks04 [339]

Step-by-step explanation:

remember, the number of possible combinations to pick m out of n elements is C(n, m) = n!/(m! × (n-m)!)

50,000 transistors.

4% are defective, that means 4/100 = 1/25 of the whole.

so, the probability for one picked transistor to be defective is 1/25.

and the probability for it to work properly is then 1-1/25 = 24/25.

now, 500 picks are done.

to accept the shipment, 9 or less of these 500 picks must be defective.

the probability is then the sum of the probabilities to get

0 defective = (24/25)⁵⁰⁰

1 defective = (24/25)⁴⁹⁹×1/25 × C(500, 1)

= 24⁴⁹⁹/25⁵⁰⁰ × 500

2 defective = (24/25)⁴⁹⁸×1/25² × C(500, 2)

= 24⁴⁹⁸/25⁵⁰⁰ × 250×499

3 defective = 24⁴⁹⁷/25⁵⁰⁰ × C(500, 3) =

= 24⁴⁹⁷/25⁵⁰⁰ × 250×499×166

...

9 defective = 24⁴⁹¹/25⁵⁰⁰ × C(500, 9) =

= 24⁴⁹¹/25⁵⁰⁰ × 500×499×498×497×496×495×494×493×492×491 /

9×8×7×6×5×4×3×2 =

= 24⁴⁹¹/25⁵⁰⁰ × 50×499×166×71×31×55×494×493×41×491

best to use Excel or another form of spreadsheet to calculate all this and add it all up :

the probability that the engineer will accept the shipment is

0.004376634...

which makes sense, when you think about it, because 10 defect units in the 500 is only 2%. and since the whole shipment contains 4% defect units, it is highly unlikely that the random sample of 500 will pick so overwhelmingly the good pieces.

is the acceptance policy good ?

that completely depends on the circumstances.

what was the requirement about max. faulty rate in the first place ? if it was 2%, then the engineer's approach is basically sound.

it then further depends what are the costs resulting from a faulty unit ? that depends again on when the defect is usually found (still in manufacturing, or already out there at the customer site, or somewhere in between) and how critical the product containing such transistors is. e.g. recalls for products are extremely costly, while simply sorting the bad transistors out during the manufacturing process can be rather cheap. if there is a reliable and quick process to do so.

so, depending on repair, outage and even penalty costs it might be even advisable to have a harder limit during the sample test.

in other words - it depends on experience and the found distribution/probability curve, standard deviation, costs involved and other factors to define the best criteria for the sample test.

3 0

2 years ago

The Wilsons traveled the 2400 miles of Route 66 from Chicago,IL to Santa Monica, CA. If their total driving time was 50 hours, w

Zolol [24]

Answer:

48 miles per hour

Step-by-step explanation:

If they traveled 2400 miles and the total driving time was 50 hours, divide 2400/50 in order to find how many miles they drove per hour.

4 0

2 years ago

Read 2 more answers