Search & Filtering
in which aspect of your life or in what personal activites can you apply the concepts of qualitative research?
Differentiate the following terms as used in categorical data analysis
1) Multinomial sampling vs binomial sampling
2)Poisson sampling process vs probability proportional to size sampling
3) Goodness of fit test vs test of association
4) relative risk vs odds ratio
Based on murder rates in Kenya, a survey has reported that the probability a new born child of eventually being a murder victim is 0.0263 for urban males, 0.0049 for rural males, 0.0072 for rural females and 0.0023 for white Urban's females.
1) Find the conditional odds ratios between region and whether a murder victim ,given gender. Interpret
2) If half the newborns are of each gender, for each region, find the marginal odds ratio between race and a whether murder victim.
Discuss circumstances under which we use chi-square in data analysis and derive the chi-square formula
In the following examples, identify the response variable and the explanatory variable illustrating their level of measurement
1) marital status(married, single, divorced, widowed), quality of life(excellent, good, fair, poor)
2) presence of disease( present, absent), gender( male, female)
Using appropriate example define the following terms used in data analysis
1) scale level measurement
2) significance level
3) a sample statistic
The density of molten salt mixtures, y g/cm3 , was measured at various temperatures x°C. The results were:
xi 250 270 290 310 330 350
yi 1.955 1.935 1.890 1.920 1.895 1.865.
Assume that the graphical checks of problem above are satisfactory.
a. Calculate the estimated variance around the regression line, �)|+ &
b. Is the estimated regression coefficient b, significantly different from zero at the 1% level of significance? Can we conclude that temperature has a significant effect on density in this case?
c. What is the 95% confidence interval for ß, the true slope or regression coefficient?
d. Calculate the 95% confidence interval for the mean value of y at each of x = 250, 300, 350.
e. Calculate the correlation coefficient for this data set.
f. Calculate the coefficient of determination.
Suppose that there are two categorical explanatory variables, sex(male and female) and handedness (right or left handed). Suppose that people coming to a shopping center are investigated, their sex registered and they are asked about being left or right handed. Let the probability that a person coming to the centre is MR,ML,FR and FL(MR means male right handed e.t.c) are 911,912,921and 922 respective. Denote Y 11 ,Y 12,Y 21 and Y 22 the numbers of MR,ML,FR and FL
a) among the 1st 1000 people
b) coming during the day.
Suppose that people come independently of each other and that the total number of people coming during the day has a possion distribution with parameter A.
Find the distribution of Y=(y11, y12, y21,y22) in case (a) and in case(b).
A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) to complete the escape: 373 370 364 366 364 325 339 393 356 359 363 375 424 325 394 402 392 369 374 359 356 403 334 397 a. Calculate the values of the sample mean and median. b. By how much could the largest time, currently 424, be increased without affecting the value of the sample median? By how much could this value be decreased without affecting the value of the sample median? c. What are the values of x̄ and the median when the observations are re-expressed in minutes?
A company tested 735 of the lightbulbs they produced and found them to have a mean life of 1,200 hours and a standard deviation of 50 hours. How many of these lightbulbs had a life between 1,170 hours and 1,230 hours?
