Can you please help me i really need help.

Milk is a good source of many vitamins that can help us stay healthy. FDA recommends that the average vitamin A concentration fo

Lelechka [254]

Answer:

The degrees of freedom for this sample are 27.

The sample size to get a margin of error equal or less than 0.3656 is n=4450.

Step-by-step explanation:

The degrees of freedom for calculating the value of t are:

$df=n-1=28-1=27$

With 27 degrees of freedom and 95% confidence level, from a table we can get that the t-value is t=2.052.

The sample size to get a margin of error equal or less than 0.3656 can be calculated as:

$MOE=t\cdot s/\sqrt{n}\\\\n=\left(\dfrac{t\cdot s}{MOE}\right)^2=\left(\dfrac{2.052\cdot 11.8841}{0.3656}\right)^2=66.7^2\\\\\\n=4449.13\approx4450$

6 0

2 years ago

Peter takes16 minutes longer to mow the lawn by himself than Charles . Together they can mow the lawn in 18 minutes. How long wi

lapo4ka [179]

Answer:

about 29.7 minutes

Step-by-step explanation:

If it take c minutes for Charles to mow the lawn by himself, it takes c+16 minutes for Peter. The two of them working together can mow in one minute this fraction of the entire lawn:

1/c + 1/(c+16) = 1/18

Multiplying by 18c(c+16), we get ...

18(c +16) + 18(c) = c(c+16)/18

36c +288 = c^2 +16c

c^2 -20c = 288 . . . . . subtract 36c

c^2 -20c +100 = 388 . . . . . add (20/2)^2 = 100 to complete the square

(c -10)^2 = 388

c = 10 +√388 ≈ 29.6977 . . . . . take the positive square root

It takes Charles about 29.7 minutes to mow the lawn by himself.

7 0

2 years ago

Hellllllppppppppppppppppppppppppppppp

larisa [96]

Answer:

c

Step-by-step explanation:

7 0

2 years ago

roberto made a 74 on last weeks math quiz. this week he made an 85 on the quiz. which best describes the percent of increase in

laila [671]

The percentage of increase in Roberto score is 14.87%, if Roberto made a 74 on last weeks math quiz. this week he made an 85 on the quiz.

Step-by-step explanation:

The given is,

Roberto score on math quiz at last week is 74

This week he made an 85 on the quiz

Step:1

Formula to calculate the percentage of increase the score,

$Percentage of increase = \frac{Final score-Starting score}{Starting score}$ × 100...........(1)

From the given,

Final score = 85

Starting score = 74

Equation (1) becomes,

$Percentage of increase =( \frac{85-74}{74})$ × 100

= $(\frac{11}{74})$ × 100

= 0.1486486 × 100

= 14.86486 %

≅ 14.87 %

Percentage of increase = 14.87 %

Result:

The percentage of increase in Roberto score is 14.87%, if Roberto made a 74 on last weeks math quiz. this week he made an 85 on the quiz.

7 0

2 years ago

Use the formula for the area of a rectangle A= lw to answer the question. A rectangle has a length of n units. Its width is 8 un

sineoko [7]

<span>It is D: n(n+4). I solved it by a long, but easy method. First, I made up the value of N, the width, and made it 3. I then added 4 to 3, which is 7. So the length is 7 and the width is 3. The area of this made up rectangle is 21. The only answer choice that has 21 as the area is D.</span>

4 0

2 years ago

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