A fifth grade teacher assumes that 15% of her students are late for class.
If the teacher is accurate, what is the probability that the proportion of late students in a sample of 555 students would be less than 14%? Round your answer to four decimal places.


=P[Z<-0.66]
=0.2546............................by using Z table or Excel =NORMSDIST(-0.66)
A fifth grade teacher assumes that 15% of her students are late for class. If the...
30% of the fifth grade students in a large school district read below grade level. The distribution of sample proportions of samples of 100 students from this population is normal with a mean of 0.30 and a standard deviation of 0.045. Suppose that you select a sample of 100 fifth grade students from this district and find that the proportion that reads below grade level in the sample is 0.36. What is the probability that a second sample would be...
A bottle maker assumes that 18% of his bottles are defective. If the bottle maker is accurate, what is the probability that the proportion of defective bottles in a sample of 626 bottles would differ from the population proportion by more than 4%? Round your answer to four decimal places.
Suppose a teacher recorded the attendance of her students in a
recent statistics class because she wanted to investigate the
linear relationship between the number of classes they missed and
their final grades. The accompanying table shows these data for a
random sample of nine students
Classes Missed Final Grade
4 73
6 81
1 92
4 72
0 94
2 86
0 89
5 87
2 96
Suppose a teacher recorded the attendance of her students in a recent...
52. In a class of 12 boys and 9 girls, the teacher selects three students at random to write problems on the board. What is the probability that all the students selected are boys? (Round your answer to four decimal places.)
The opera theater manager assumes that 10% of the opera tickets for tonight's show have been sold. If the manager is right, what is the probability that the proportion of tickets sold in a sample of 429 tickets would be less than 6%? Round your answer to four decimal places.
An AP Statistics teacher claims that the AP Statistics grade distribution is as follows: Grade Percentage 5% 20% 40% 15% Suppose that a sample of 100 students taking AP Statistics class yields the observed counts shown below: Grade Number of Students 17 25 35 15 Use a 0.10 significance level to test the claimed AP Statistics grade distribution is correct (a) Identify the appropriate hypothesis test and explain the reasons why it is appropriate for analyzing this data. (b) Identify...
The reading speed of second grade students in a large city is approximately normal, with a mean of 91 words per minute (wpm) and a standard deviation of 10 wpm. Complete parts (a) through (f). (a) What is the probability a randomly selected student in the city will read more than 96 words per minute? The probability is nothing. (Round to four decimal places as needed.) Interpret this probability. Select the correct choice below and fill in the answer...
A bottle maker believes that 15% of his bottles are defective. If the bottle maker is accurate, what is the probability that the proportion of defective bottles in a sample of 561 bottles would be less than 11%? Round your answer to four decimal places.
A teacher wants to predict a students grade average for her class cased on the number of hours that the student missed class.. She computes the regression equation to be y = - 2.5x + 105 a. What is the students predicted average if they miss 6 hours of class? b. The correlation coefficient for the problem is? Make an estimate, then explain what this means in terms of the situation? c. What does the slope mean in terms of the...
A teacher wants to predict a students grade average for her class cased on the number of hours that the student missed class.. She computes the regression equation to be y = -2.5x + 105 a. What is the students predicted average if they miss 6 hours of class b. The correlation coefficient for the problem is? Make an estimate, then explain what this means in terms of the situation c. What does the slope mean in terms of the...