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the population standard deviation is estimated by the sample standard deviation of eight hours what is the probability that the difference between the sample mean and the population mean
If possible use diagrams to aid calculations.
4. In a raffle there is one first prize of $100, one second prize of $50 and one third prizeof $10. There are 100 tickets sold and first prize is drawn first, then second, then.
third, without replacement. Find the probability that a person buying one ticket in.
the raffle wins.
(a) first prize;.
(b) a prize;.
(c) at least $50.
The 35 learners in a grade 7 class wrote an English test out of 60. The marks are as follows: 14 20 27 31 33
40 40 41 41 41
41 42 42 46 46
49 50 51 51 52
53 54 54 56 56
57 58 59 59 60
60 60 60 56 43
Use the data above to answer me following questions:
2.1 is the data discrete or continuous? Substantiate your answer.
2.2 which graph(s) will best display this type of data? Substantiate your answer.
2.3. Calculate the following:
2.3.1. The mean ( correct to three decimal place)
2.3.2. The median
2.3.3. The mean
2.4 which is the best measures of the central tendency for this- the mean or median? Explain your answer.
2.5. Calculate the following:
2.5.1 the variance ( correct to three decimal places)
2.5.1 the interquartile range.
2.6. Use the class intervals 1_< x _< 19 , 20 _< x _<29,30 _< x _< 39 , etc ,to construct a frequency table for the English test marks of the 35 learners.
In some states, the law requires drivers to turn on their headlights when driving in the rain. A highway patrol officer believes that less than one-quarter of all drivers follow this rule. As a test, he randomly samples 200 cars driving in the rain and counts the number whose headlights are turned on. He finds this number to be 41. Does the officer have enough evidence at the 10% significance level to support
his belief?
Has the recent drop in airplane passengers resulted in better on-time performance? Before the recent downturn one airline bragged that 92% of its flights were on time. A random sample of 165 flights completed this year reveals that 153 were on time. Can we conclude at the 5% significance level that
the airline’s on-time performance has improved?
Two fair dice are thrown independently. Three events A, B and C is defined as
follows :
A: Even face with first dice.
B: Even face with second dice.
C: Sum of the points on the two dice is odd.
Discuss the independence of events A, B and C.
A research team studying the relationship between blood type and severity of a certain condition in a population collected data on 1500 subjects as displayed in the contingency table shown as Table 1. Table 1 Severity Of Condition Blood Type A B AB O Absent 543 211 90 476 Mild 44 22 8 31 Severe 28 9 7 31 The researcher wished to know if these data were compatible with the hypothesis that severity of condition and blood type are independent.
What is the number of possible samples from the given: N = 7, n=3.
- A stockroom clerk returns three safety helmets at random to three steel mill employees who had previously checked them. If Smith and Brown , in that order, receive one of the three hats. Find the probability distribution of the random variable that represents the number of correct matches.
1. Given the normally distributed variable X with mean 18 and variance 6.25. find
a) P(X is less than15)
b) THE VALUE OF K SUCH THAT P(X is less than k) = 0.2236
c) P(17 less than X less than 21)
