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Montano1993 [528]
3 years ago
15

Jessica knows that the adult population gets, on average, eight hours of sleep each night. A hypothesis test can help her see if

college students are different from the adult population. Jessica tabulated that her sample of 101 students got an average of 6.9 hours of sleep each night, with a standard deviation of 2.5. Using the data provided and the formula below, what is the t-statistic that Jessica calculates? Answer choices are rounded to the hundredths place.
Mathematics
1 answer:
Nitella [24]3 years ago
6 0

Answer:

-4.42

Step-by-step explanation:

Given the following :

Population mean (pm) = 8 hours

Sample mean (sm) = 6.9 hours

Number of observations (n) = 101 students

Sample standard deviation (sd) = 2.5

Using the t-statistic formula :

[(sm - pm) / (sd/√n)]

Hence,

[(6.9 - 8) / (2.5/√101)]

[(-1.1) / (2.5/10.05)]

-1.1 / 0.2487562

= −4.422

The test statistic = - 4.42 to the nearest hundredth.

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ruslelena [56]
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5(17-2)=75

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4 0
3 years ago
1) Let f(x)=6x+6/x. Find the open intervals on which f is increasing (decreasing). Then determine the x-coordinates of all relat
brilliants [131]

Answer:

1) increasing on (-∞,-1] ∪ [1,∞), decreasing on [-1,0) ∪ (0,1]

x = -1 is local maximum, x = 1 is local minimum

2) increasing on [1,∞), decreasing on (-∞,0) ∪ (0,1]

x = 1 is absolute minimum

3) increasing on (-∞,0] ∪ [8,∞), decreasing on [0,4) ∪ (4,8]

x = 0 is local maximum, x = 8 is local minimum

4) increasing on [2,∞), decreasing on (-∞,2]

x = 2 is absolute minimum

5) increasing on the interval (0,4/9], decreasing on the interval [4/9,∞)

x = 0 is local minimum, x = 4/9 is absolute maximum

Step-by-step explanation:

To find minima and maxima the of the function, we must take the derivative and equalize it to zero to find the roots.

1) f(x) = 6x + 6/x

f\prime(x) = 6 - 6/x^2 = 0 and x \neq 0

So, the roots are x = -1 and x = 1

The function is increasing on the interval (-∞,-1] ∪ [1,∞)

The function is decreasing on the interval [-1,0) ∪ (0,1]

x = -1 is local maximum, x = 1 is local minimum.

2) f(x)=6-4/x+2/x^2

f\prime(x)=4/x^2-4/x^3=0 and x \neq 0

So the root is x = 1

The function is increasing on the interval [1,∞)

The function is decreasing on the interval (-∞,0) ∪ (0,1]

x = 1 is absolute minimum.

3) f(x) = 8x^2/(x-4)

f\prime(x) = (8x^2-64x)/(x-4)^2=0 and x \neq 4

So the roots are x = 0 and x = 8

The function is increasing on the interval (-∞,0] ∪ [8,∞)

The function is decreasing on the interval [0,4) ∪ (4,8]

x = 0 is local maximum, x = 8 is local minimum.

4) f(x)=6(x-2)^{2/3} +4=0

f\prime(x) = 4/(x-2)^{1/3} has no solution and x = 2 is crtitical point.

The function is increasing on the interval [2,∞)

The function is decreasing on the interval (-∞,2]

x = 2 is absolute minimum.

5) f(x)=8\sqrt x - 6x for x>0

f\prime(x) = (4/\sqrt x)-6 = 0

So the root is x = 4/9

The function is increasing on the interval (0,4/9]

The function is decreasing on the interval [4/9,∞)

x = 0 is local minimum, x = 4/9 is absolute maximum.

5 0
3 years ago
Given m || n, find the value of x and y
Serjik [45]

Step-by-step explanation:

5x-6+7x+18=180

12x=180+6-18

12x=168

168÷12=14

X=14

for y

3y+11=7x+18(7×14+18)

3y+11=116

3y=116-11

3y=105

y= 35

5 0
3 years ago
6) The amount of Jen's monthly phone bill is normally distributed with a mean of $70 and a standard
alexandr402 [8]

Answer:

i)The correct option is  D.) 99.74%

ii) The correct option is B.) 68.26%

Step-by-step explanation:

i) P(10≤X≤70) = P(  (10−40)/10  ≤Z≤   (70−40 )/10 ) =  Pr(−3≤Z≤3)

= 0.9987 - 0.0013 = 0.99734

Therefore the percentage of Jen's monthly phone bills are between $40 and $100 is D.) 99.74%

ii)P(2.1≤X≤3.1) = P(  (2.1 − 2.6) /0.5   ≤ Z  ≤ (3.1−2.6 )/0.5)  =  Pr(−1  ≤Z  ≤1) )

=  0.8413 − 0.1587  =  0.6826

Therefore the percentage of students at college have a GPA between 2.1 a,d 3.1 is B.) 68.26%

5 0
3 years ago
Marcie jogs each morning. The relationship between the total number of miles she jogged this week, m, to the total number of mil
Phantasy [73]

Answer: Marcie jogged twice as many miles this week as she jogged last week

Step-by-step explanation:

5 0
3 years ago
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