Questions and Answers

What is crossing over? Give its significance.

What is recombination frequency?

Explain how Bridges’s study of non disjunction in Drosophila helped prove the chromosome theory of inheritance.

How did nondisjunction experiments help to prove the chromosome theory of inheritance? Drosophila in which nondisjunction was seen were more likely to have wild type phenotypes than others. b) Bridges isolated genetic mutants of eye color and was able to sequence the mutants. c) The results of nondisjunction were seen on d) Bridges isolated exceptional Drosophila offspring with extra or missing chromosomes and was able to analyze the phenotypes based upon these genotypes. e) Bridges isolated Drosophila with no X chromosome and was able to identify the phenotypes. What is the phenomenon hyperactivation? When a gene is overexpressed in the homozygous dominant. b) In incomplete dominance, the homozygous dominant has a more intense phenotype than the heterozygote. c) In male mammals, when the genes on the chromosome are upregulated in such a way as to match the expression from the two chromosomes in the female. d) When a gene is overexpressed in response to a disease state. e) In male Drosophila, when the genes on one chromosome are upregulated in such a way as to match the expression from the two X chromosomes of the Drosophila female. What is the chromosomal ratio required for wild type male Drosophila to develop? 2X:LY IXZA 2Xila 0.5X:LY IX:1Y

H0: pXL=0.10, pL=0.20, pM=0.40, pS=0.20, pXS=0.10 How many medium rubber bands are expected in the random sample of 450 rubber bands?
A) 20
B) 40
C) 90
D) 180
E) 1,125

The manager conducts a goodness-of-fit test to determine whether the proportions of workers of these types are identical to the population proportions of workers donating to charity, which are 50 percent for management, 30 percent for other white-collar workers, and 20 percent for blue-collar workers. Which of the following statements must be true about the sample?
A) The expected number of blue-collar workers donating to charity is less than 30.
B) The expected number of management workers donating to charity is 100.
C) The expected numbers of other white-collar and blue-collar workers donating to charity are the same.
D) The expected number of other white-collar workers donating to charity is 50.
E) The combined expected numbers of other white-collar and blue-collar workers donating to charity is greater than the expected number of management workers donating to charity.

A reporter intends to survey residents of a city to investigate whether there are differences in use of grocery delivery services by region of the city where the residents live (north, south, west, and east). City residents will be asked to respond yes or no to the question “Do you regularly use a grocery delivery service to purchase groceries?” Results will be collected in a 4-by-2 table of counts organized by region and response to the question. For a chi-square test for homogeneity, which of the conditions listed below is not necessary to investigate whether there are differences between use of grocery delivery service by region?
A) For each cell in the table, (row total)(column total)/table total will be greater than 5.
B) Data should be collected using a stratified random sample, with region as strata.
C) All eight expected cell counts should be greater than 5.
D) The number of residents sampled from each region should be greater than 30.
E) The total number of residents sampled should be at most 10 percent of the total number of residents in the city.

A company claims that 50 percent get a basic audit, 30 percent get an enhanced audit, and 20 percent get a complete audit. The company tests this hypothesis using a random sample and finds χ2=0.771 with a corresponding p-value of 0.68. Assuming conditions for inference were met, which of the following is the correct interpretation of the p-value?
A) There is a 68 percent chance of obtaining a chi-square value of at least 0.771.
B) There is a 68 percent chance that the company’s claim is correct.
C) If the null hypothesis were true, there would be a 68 percent chance that the company’s claim is correct.
D) If the null hypothesis were true, there would be a 68 percent chance of obtaining a chi-square value of 0.771.
E) If the null hypothesis were true, there would be a 68 percent chance of obtaining a chi-square value of at least 0.771.

A χ2 goodness-of-fit test proportions was used to test the hypothesis that students at a local university select majors in the same as other universities in the state. A chi-square test statistic of χ2=45.6 was calculated with a corresponding p-value of 0.005. Which of the following is correct?
A) There is sufficient evidence to conclude that students at the local university do not select majors in the same proportions as do students in the rest of the state.
B) There is sufficient evidence to conclude that students at the local university select majors in the same proportions as do students in the rest of the state.
C) There is insufficient evidence to conclude that students at the local university do not select majors in the same proportions as do students in the rest of the state.
D) There is insufficient evidence to conclude that students at the local university select majors in the same proportions as do students in the rest of the state.
E) Students at the local university select majors in the same proportions as do students in the rest of the state.

A chi-square test was conducted to investigate whether there is an association between a person’s favorite flavor of ice cream and their favorite toppings. Each of 200 randomly selected customers at an ice cream parlor was asked to pick their favorite flavor from vanilla, chocolate, chocolate chip, or none of these. They were also asked to pick their favorite topping from chocolate sauce, peanuts, crumbled cookies, crushed candies, or none of these. The hypothesis test had a test statistic of 24.97 with an associated p-value of 0.015. If the significance level of the test was α=0.05, which of the following is the correct decision for this hypothesis test?
A) There is not convincing statistical evidence to suggest an association between favorite ice cream flavor and favorite topping.
B) There is convincing statistical evidence to suggest an association between favorite ice cream flavor and favorite topping.
C) There is convincing statistical evidence to suggest there is not an association between favorite ice cream flavor and favorite topping.
D) There is proof that a person’s favorite ice cream topping is dependent on the person’s favorite ice cream flavor.
E) There is proof that a person’s favorite ice cream topping is independent of the person’s favorite ice cream flavor.