Chi Squared & Experimental Design

What is the null hypothesis for this experiment?

• Ground type and distance has no effect on the percent of reflected light

• Percent of reflected light has no effect on the ground type

• There is no statistical difference between the reflective ground cover and distances above the ground.

• There is a difference between the percent of light reflected and the ground type.

What is the expected ratio in a chi-squared test for genetic linkage in a dihybrid cross?

• 3:1 ratio of dominant to recessive traits

• 9:3:3:1 ratio of phenotypic traits

• 1:1 ratio of alleles in a population

• 1:1:1:1 ratio of phenotypic traits

What is the critical value for a chi-squared test given table 1 and a significance level of 0.05?

• 5.99

• 7.81

• 9.21

• 11.34

What is the chi-squared test used to analyze in genetics?

• Heritability

• Gene expression

• Genetic linkage

• Protein synthesis

Ecologists often wonder if species are associated with each other. The presence or absence of two species of scallop was recorded in fifty quadrats (1m²) on a rocky sea shore 

The following distribution pattern was observed:

6 quadrats = both species  ;  15 quadrats = king scallop only  ;  20 quadrats = queen scallop only  ;  9 quadrats = neither species 

What is the alternative hypothesis?

• There is no significant difference between the distribution of two species (i.e. distribution is random)

• There is a significant difference between the distribution of species (i.e. species are associated)

• The presence of plankton has no effect on the type of scallop found in the sample.

• There is an association between clams and mussels.

If the chi squared value is greater than the critical value then you can

• Reject the Ho

• Accept the Ho

A researcher wants to test if the observed distribution of eye color in a population fits the expected distribution based on a genetic model. The critical value with a 95% confidence level and 4 degrees of freedom is 9.49. If the calculated chi-squared value is 9.2, what should the researcher do?

• Reject the null hypothesis

• Accept the null hypothesis

• Modify the null hypothesis

• Collect more data

• Fail to reject the null hypothesis

What can we say about the location of the genes involved in eye and body morphology (shape)?

• The genes are located close together on the same chromosome

• The genes are located on separate chromosomes

• The genes are linked on the same chromosome

• Need more information