1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Grace [21]
3 years ago
11

Professor smith conducted a class exercise in which students ran a computer program to generate random samples from a population

that had a mean of 50 and a standard deviation of 9 mm. each of smith's students took a random sample of size n and calculated the sample mean. smith found that about 68% of the students had sample means between 48.5 and 51.5 mm. what was n? (assume that n is large enough that the central limit theorem is applicable.)
Mathematics
1 answer:
Advocard [28]3 years ago
4 0
When xbar is 48.5

-1 is (48.5 - 50)/(9/sqrt n)
-9/sqrt n is -1.5
n is (9/1.5²) is 36

when xbar is 51.5
+1 is (51.5 - 50)/(9/sqrt n)
9/sqrt n is1.5
n is (9/1.5)² is 36
You might be interested in
A disc has a diameter of 21 cm while a mini disc has a diameter of 14cm. Write the ratio of the mini disc diameter to the disc d
Serjik [45]

Answer:

mini disc diameter:disc diameter

14cm:21cm = 7:10.5 = 3.5:5.25 = 1:1.5

4 0
2 years ago
Suppose John is a high school statistics teacher who believes that watching many hours of TV leads to lower test scores. Immedia
Hatshy [7]

This question is incomplete, the complete question is;

Suppose John is a high school statistics teacher who believes that watching many hours of TV leads to lower test scores. Immediately after giving the most recent test, he surveyed each of the 24 students in his class and asked them how many hours of TV they watched that week. He then matched each student's test grade with his or her survey response. After compiling the data, he used hours of TV watched to predict each student's test score. He found the least-squares regression line to be y"  = -1.5x + 85.

He also calculated that the value of r, the correlation, was -0.61.

what is the correct value of the coefficient of determination R² and give a correct interpretation of its meaning

Answer:

Interpretation of coefficient of determination R² = 0.3721

R² = 0.3721, meaning 37.21% of the total variation in test scores can be explained by the least square regression line

Step-by-step explanation:  

Given the data in the question;

the least square regression line is;

y"  = -1.5x + 85

the correlation coefficient r = -0.61

Now, the coefficient of determination R² is square of correlation coefficient r

R² = -61²

R² = 0.3721

8 0
2 years ago
Geometry
Mademuasel [1]
DB is a median (given). It goes from vertex point D to midpoint B. 

The point B is the midpoint of segment AC. So B cuts AC into two equal halves: AB and AC
Meaning AB = AC

AC = AB+BC ... segment addition postulate
AC = AB+AB ... substitution; replace BC with AB (valid because AB = AC)
AC = 2*AB
2*AB = AC
2*AB = 50 ... substitution; replace AC with 50
2*AB/2 = 50/2 ... divide both sides by 2
AB = 25 which is the answer
6 0
2 years ago
Help plz:)))I’ll mark u Brainliest
noname [10]

Answer:

22-18-25,

19-24-30,

7-24-25

Step-by-step explanation:

In a triangle with side lengths a, b, and c, any two sides must have a sum larger than the third.

Using this rule, the possible side lengths out of these choices that could form a triangle are:

22-18-25,

19-24-30,

7-24-25

7 0
2 years ago
What were some of the challenges pilgrims faced on their journey
EleoNora [17]

On the ocean Pilgrims encounter fierce storms, disease, and their ship falls into disrepair. During the first winter they lack shelter, warmth, and food.

The Pilgrims struggled to build homes, and many families crowded into the few homes that were built. Food was scarce, and many Pilgrims starved to death that first winter.

Hope this helped

3 0
3 years ago
Other questions:
  • Find the measure of an exterior angle of a regular polygon with 20 sides. Round to the nearest tenth ?
    13·2 answers
  • A bag contains 7 red marbles, 4 white marbles, and 11 blue marbles. Find P ( not red).
    11·1 answer
  • Find the product. Simplify using positive exponents.<br><br><br> 4⁴ · 4³<br><br><br> 2² · 2⁻⁴
    8·1 answer
  • Which is the simplified form of the expression (6 to the power of -2 times 6 to the power of 5) to the -3rd power?
    7·2 answers
  • A farmer has an apple orchard consisting of Fuji and Gala apple trees. Due to high winds this year 10% of his trees cross pollin
    12·1 answer
  • 6,859^1/3 can be written as
    15·1 answer
  • Harry collected data from a random sample of seventh graders at his school. Out of 25 respondents, 10 of them ride the
    7·1 answer
  • Mr. Muñoz has a coupon for 15% off his entire purchase. He buys binoculars for $105 and hiking boots. He spends a total of $170
    10·1 answer
  • John spent about 12.5 hours at a water park. He estimated he spent about 30% of the time waiting in line. What would be a reason
    15·1 answer
  • PLS HELP ME ASAP I DONT HAVE TIME. IT ALSO DETECTS IF ITs RIGHT OR WRONG.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!