Question

Chapter 8: Chi­Square Name: Review questions for article: Heavey, E. Moysich, K., Hyland, A., Druschel, C., & Sill, M. (2008). Differences in pregnancy desire among pregnant female adolescents at a state­funded family planning clinic. Journal of Midwifery & Women’s Health, 53(2), p. 130­137.

Answer 1

The Chi-Square test is typically used to analyze the relationship between two variables under the following conditions such as :

a)Both variables are qualitative in nature(that means, measured on a nominal level)

b)The two variables have been measured on the same individuals

c)The observations on each variable are between-subjects in nature

Chi-square test is :

*non-parametric in nature

*designed to analyze the relationship between two variables using frequency information

Inference of a relationship using the Chi-Square Test: is :

1) State a null hypothesis
2) Obtain a set of observed frequencies
3) Derive a set of expected frequencies based in the assumption that the null hypothesis is true
4) Compare the expected frequencies with the observed frequencies
5) Reject the null hypothesis if the overall difference between the observed frequencies and the expected frequencies is large (as defined by a given alpha level)

Chi-square statistic reflects the overall differences between the observed and expected frequencies.

#Research based on "Differences in pregnancy desire among pregnant female adolescents at a state-funded family planning clinic"

Research has suggested the importance of pregnancy desire in explaining pregnancy risk behavior among adolescent females. Much of the literature, however, uses cross-sectional study designs to examine this relationship. Because bias may strongly influence these results, more prospective studies are needed to confirm the relationship between pregnancy desire and pregnancy incidence over time.

Methods:

Non-pregnant adolescents aged 14-19 years (N=208) completed baseline interviews and interviews every 6 months thereafter for 18 months.

Participant characteristics by incident pregnancy (n=162)¹

	Incident Pregnancy (n=38)	No Incident Pregnancy (n=124)	p-valuea
Age (years)	17.2 $\tiny \pm$ 1.32	17.2 $\tiny \pm$ 1.50	0.269
Race			0.236
Non-Hispanic White	4(10.5%)	21 (16.9%)
Non-Hispanic Black	12 (31.6%)	53 (42.7%)
Hispanic	16 (42.1%)	40 (32.3%)
Other	6(15.8%)	10 (8.1%)
Below poverty	28(73.7%)	96 (77.4%)	0.634
Currently in school	25 (65.8%)	101 (81.5%)	0.042*
Employed	12 (31.6%)	61 (49.2%)	0.056
*Children in home			0.462
0	8 (21.1%)	19 (15.3%)
1	13 (34.2%)	32 (25.8%)
2	7(18.4%)	35 (28.2%)
3 or more	10(26.3%)	38 (30.6%)
*Relationship duration (follow up)			0.030*
No relation	6(15.8%)	32 (25.8%)
Less than 6 months	7 (18.4%)	7 (5.6%)
Between 6 to 12 months	1 (2.6%)	13 (10.5%)
12months or more	24 (63.2%)	72 (58.1%)
Ever Pregnant	14 (36.8%)	25 (20.2%)	0.035*
Alcohol Use (past 30 days)	12 (31.6%)	52(41.9%)	0.253
Marijuana Use (past 30 days)	19 (50.0%)	44 (35.5%)	0.108
Age at first sex (years)	12.9 $\tiny \pm$ 2.24	12.8 $\tiny \pm$ 2.00	0.798
Number of sex partners (ever)	4.7 $\tiny \pm$ 5.53	4.4 $\tiny \pm$ 4.32	0.742
Perceives stress	3.1 $\tiny \pm$ 0.59	3.0 $\tiny \pm$ 0.59	0.291
Self-Esteem	3.9 $\tiny \pm$ 0.69	4.0 $\tiny \pm$ 0.65	0.454
Depression	8.9 $\tiny \pm$ 5.48	7.5 $\tiny \pm$ 5.71	0.175
Anxiety	8.1 $\tiny \pm$ 5.66	6.1 $\tiny \pm$ 4.95	0.037*
Positive Coping	5.6 $\tiny \pm$ 1.20	5.5 $\tiny \pm$ 1.13	0.770
Negative Coping	4.6 $\tiny \pm$ 1.37	4.1 $\tiny \pm$ 1.34	0.064
Pregnancy Desire	15 (39.5%)	24 (19.4%)	0.011*

P<0.05

Results:

Twenty-four percent of participants either desired pregnancy or were ambivalent towards pregnancy. Pregnancy desire was associated with older age, relationship duration of fewer than 6 months and higher perceived stress.