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A company producing handheld electronic devices (tablets, mobile phones etc.) wants to understand how people of different ages rate its products. For this reason, the company’s management has decided to use a survey of its customers and has asked you to devise an appropriate random sampling scheme. Outline the key components of your sampling scheme.
The mean and standard deviation of serum iron values which are normally distributed for a random sample of 50 healthy men are 120 and 15 micrograms respectively. Find 95% confidence limits within the population mean. (z=1.96)
If the incidence of diabetes mellitus is 1% per
year and its approximate duration is 5 years, then
what is its expected point prevalence?
In a group of 40 subjects screened for noncommunicable diseases, 10 are healthy and every
person of the remaining 30 has either high blood
pressure, a high level of cholesterol or both. You
were further informed that 15 have high blood
pressure and 25 have a high level of cholesterol.
If a person is selected randomly from this group of
subjects, what is the probability that he or she has
either high blood pressure or high level of
cholesterol?
It is known from the records of the city schools that the standard deviation of mathematics test scores on problem solving is 5. A sample of 200 bright students was taken and it was found out that the sample mean score is 75. Previous test showed out the population mean to be 70. Is it safe to conclude at 0.025 level of significance that the sample is significantly different from the population?
Using practical examples from the field of statistics, determine the following variables you expect to have a normal or nearly normal distribution. Illustrate by discussing and explaining possible reasons for your answer.
a. Scores on a very easy test
b. Shoe sizes of a random sample of adult women
c. The number of apples in each of 100 full bushel baskets
Suppose that on average every hour 10 customers enter a departmental store.
a. Calculate the probability that in an hour 12 customers entered the Store.
Before you proceed, let us check your readiness for this lesson. Below is a 5-
item true or false test. Determine whether the statement is true or false. Write T if the
statement is true and F if false on the blank provided before each number.
1. The z-score measures how many standard deviation a given value is above
or below the mean.
2. A negative z-score indicates that the score or value is above the mean.
3. If a z-score is equal to −2.05, it is 2.05 standard deviations below the
mean.
4. A positive z-score indicates that the score or value is below the mean,
5. If a z-score is 0, it is on the mean.
Before you proceed, let us see how much you know before we tackle the lesson.
Below is a 5-item true or false test. Determine whether the statement is true or false.
Write T if the statement is true and F if false on the blank provided before each number.
1. Regions under the curve can be described in terms of area.
2. Under the normal curve, the areas at the tails are minimal.
3. The area of the region between 𝑧 = 0 and 𝑧 = 1 is 0.3643.
4. The area of the region below mean is 0.6.
5. Areas under the normal curve are positive values.
Fill in the blanks with the appropriate word or phrase to make a meaningful
statement.
1. The distribution curve is a_________
probability distribution.
2. The area under the curve is________.
3. The width of the curve is determined by the___________of the distribution.
4. The curve is__________to the base line.
5. The area to the left of z = 0 (or to the right of z = 0) is_____________.
6. The curve is___________about its center.
7. The mean, median, and mode of the normal curve are_____________.
8. The area between z = 0 and z = 1 is _______________.
9. The table of areas under the normal curve is also called____________.
10.The standard normal curve is a normal probability distribution that has a mean
of_____________and standard deviation of_____________.
#340153 on Dec 2023