EASY
Earn 100

A television channel claims that 25% of its programmes are nature programmes. Yolande thinks the percentage claimed is too high. To test her hypothesis, she chooses 20 programmes at random.

If Yolande carries out the hypothesis test at the 10% significance level, define the random variable, state its distribution, including parameters, and define the hypotheses.

Important Questions on Hypothesis Testing

MEDIUM

Chief Educational Officer wanted to study the performance of XII Standard students in Mathematics subject. The following are the information obtained from randomly selected students from two Educational Districts.

Educational
District
No. Of students.
selected
Mean Standard
Deviation
A 45 62 15
B 53 60 17

Examine at 5% Level of significance whether students in District A perform better compared to students in District B.

MEDIUM
Interest of XII Students on Residential Schooling was investigated among randomly selected students from two regions. Among 300 Students selected from Region A, 34 Students expressed their interest. Among 200 Students selected from Region B, 28 Students expressed their interest. Does this information provide sufficient evidence to conclude at 5% Level of significance that students in Region A are more interested in Residential Schooling than the students in Region B?
MEDIUM
How will you formulate the hypotheses for testing equality of means of two populations, when the population variances are known? Describe the method.
MEDIUM
One thousand apples kept under one type of storage were found to show rotting to the extent of 4% and 1500 apples kept under another kind of storage showed 3%rotting. Can it be reasonably concluded at 5%Level of significance that the second type of storage is superior to the first?
MEDIUM
A District Administration conducted awareness campaign on a contagious disease utilising the services of school students. Among 64 randomly selected households, 50 of them appreciated the involvement of students. Can the District administration decide whether more than 90% success could be achieved in these kinds of program by involving the students? Fix the level of significance as 1%.
MEDIUM
Give a detailed account on testing hypotheses for population proportion.
MEDIUM
The mean yield of rice observed from randomly selected 100 Plots in District A was 210 Kg per acre with standard deviation of 10 Kg per acre. The mean yield of rice observed from randomly selected 150 Plots in District B was 220 Kg per acre with standard deviation of 12 Kg per acre. Assuming that the standard deviation of yield in the entire state was 11Kg, test at 1% Level of significance whether difference between the mean yields of rice in the two districts is significant.
EASY

If μ denotes the population mean, then find the critical value to be used for testing H0:μ=100 against H1:μ<100 based on 250 observations at 5% level of significance.

MEDIUM
A coin is tossed 10, 000 Times and head turned up 5195 Times. Test the hypothesis at, 5% Level of significance, that the coin is unbiased.
MEDIUM

Carry out hypothesis testing exercise for testing H0:μX=μY against H1:μXμY with usual notations, when x¯= 7 and y¯=8 ,σ x=3 and σy =2and m=40 and n=40. Use α=0.01.

MEDIUM

A study was conducted among randomly selected families who are living in two locations of a district, and parents were asked “Whether watching TV programs by parents affects the studies of their children?” Details are presented here under:

Locality No. Of Families.
Contacted Agreed
A 200 48
B 600 96

Test, at 5% level of significance, whether the difference between the proportions of families in the two localities agreed the statement.

MEDIUM

Preference of school students, who participate in Sports events, to do physical exercises in Modern Gymnasium rather than doing aerobic exercises was analyzed. The number of students randomly selected from two States and their preference for Modern Gymnasium are given below.

State No. Of Students.
Sampled  Preferred Modern Gymnasium
A 50 38
B 60 52

Test whether the difference between proportions of school students who prefer Modern Gymnasium to do their exercises in the two States is significant at 5% level of significance.

MEDIUM
Explain the procedure of testing hypotheses for equality of proportion of two populations.
MEDIUM
A machine assesses the life of a ball point pen, by measuring the length of a continuous line drawn using the pen. A random sample of 80 pens of Brand A have a total writing length of 96.84 Km. Random sample of, 75 Pens of Brand B have a total writing length of 93.75 Km. Assuming that the standard deviation of the writing length of a single pen is 0.15 Km for both brands, can the consumer decide to choose Brand B pens assuming that their average writing length is more than that of Brand A pens? Set level of significance as 1%.
EASY

 Formulate the null and alternative hypotheses for testing whether the average time required to XI standard students to complete a Chemistry laboratory exercise is less than 30 minutes

MEDIUM
A special training program was organised by a district educational officer to the VIII standard students for improving their skill in Letter Writing. Time taken by the students in a letter writing competition was recorded. The average time taken by 100 randomly selected students was15 minutes. Can the Officer decide that at 1% level of significance the mean time in this kind of exercise required to VIII students of the district is 13 minutes, assuming the population standard deviation as 8 minutes?
MEDIUM

Represent the union of two sets by Venn diagram for each of the following.

X={x | x is a prime number between 80 and 100}

Y={y | y is an odd number between 90 and 100}

EASY

In test for two population proportions, if m=100n=150, mpX=78, npY=100 and then calculate the value of the test statistic under H0:PX=PY.

MEDIUM
Describe the procedure for testing hypotheses concerning equality of means of two populations, assuming that the population variances are unknown.
MEDIUM

A study was conducted to compare the performance of athletes of two States in InterState Athlete Meets. Details of the number of successes achieved by the athletes of the two States are given here under:

State No. Of Athletes. Mean Standard Deviation
State-1 300 75 10
State-2 400 73 11

Does the above information ensure at 1% level of significance that the difference between the performances of the athletes of the two States is significant?