MCQs on Biostatistics Part 1

# Which of the following correlates highest correlation between variables ?
A. r= + 0.25
B. r= + 0.5
C. r= - 0.75
D. r= + 2

# The arithmetical average of a number of observations is called :
A. Mean
B. Median
C. Range
D. All of the above

# Which of the following is not a measure of central tendency ?
A. Mean
B. Mode
C. Range
D. Median

# The levels of nicotine in 6 cigarettes were 13.0, 11.8, 15.4, 17.4, 31.2 and 24.3 mg. The mean of these values is:
A. 14.9
B. 15.9
C. 18.6
D. 8.4

# Father of Health Statistics is:
A. John Snow
B. John Graunt
C. Frederick Mc Kay
D. Pierre Fauchard

# Ranking students from the individual with the highest Grade points average (GPA) to the lowest is an example of:
A. Ordinal Scale
B. Nominal Scale
C. Interval Scale
D. Ratio Scale

# A random sample suggests that :
A. A person in a control group will not be a member of the experimental group
B. Any member of a group to be studied has an equal opportunity to be included in the study
C. Every nth name on a list is selected
D. Subjects are volunteers

# A stastistical test which indicates the chance or probability of an observed difference between two means occuring by chance is called:
A. Tests of significance
B. Means
C. Ratio
D. Normalcy

# Best measure for central tendency in a highly skewed distribution is :
A. Median
B. Mean
C. Mode
D. Range

# The graphic representation of frequency distribution with X and Y axis is :
A. Frequency polygon
B. Histogram
C. Pictograph
D. Pie diagram

> # A series may have all except :
A. No mode
B. One mode
C. Many modes
D. Negative mode

# The correlation coefficient can range from :
A. 0 to +1
B. 0 to -1
C. -1 to +1
D. 0 to 100

# As the sample size increases, standard deviation :
A. Decreases
B. Increases
C. Remains the same
D. May increase or decrease

# In a 3*3 table, the number of degrees of freedom is:
A. 4
B. 9
C. 3
D. 81

# Most of the values in data spread along the :
A. Mean
B. Mode
C. Median
D. Arithmatic mean

Local Anesthetic Techniques

Technique	Features
1. Infiltration	Also called as submucosal analgesia. Terminal branches or free nerve endings are anesthetized. Only that area into which the local anesthetic solution is infiltrated is anesthetized.
2. Field Block	Large Terminal Branches are anesthetized.
a) Paraperiosteal	Most commonly used technique. The solution is deposited alongside the periosteum. It is indicated widely in the porous maxilla than in the dense mandible.
b) Interosseous	Means injecting directly into the bone. Painful and dangerous procedure. It is not commonly used.
c) Interseptal	It is most effective in children and young adults. LA is injected into the thin porous interseptal bone.
d) Intraligamentary	Most effective for anesthetizing single tooth by injecting LA into the periodontal ligament under high pressure.
e) Intrapulpal	LA is injected into the pulp chamber. The needle should be wedged firmly.

Must know Facts about Local Anesthetics / LA

This table lists some unique properties of local anesthetic agents.

Properties	Local Anesthetic
Natural local anesthetic agent	Cocaine
Local anesthetic agent with intrinsic vasoconstriction property	Cocaine
LA which is most dilating of all	Procaine

List of Medical Syndromes and their Important Features

1. Developmental Disturbances

Syndrome	Important Features
Parry Romberg's Syndrome	Facial Hemiatrophy
Vander Woude's Syndrome	Pits of lower lip and cleft of palate
Ascher's Syndrome	Acquired double lip + Blepharochalasis + Non toxic thyroid enlargement
Oro Facial Digital Syndrome	Cleft tongue nd clefting of mandibular alveolar process
Median Cleft Face Syndrome	Hypertelorism + Median cleft of premaxilla, palate + Cranium bifidum occultum
Meischer's Syndrome	Cheilitis granulomatosa

Setting time of Dental Materials : Alginate setting time, GIC, ZOE, Impression plaster and Zinc Phosphate Setting Time

The Setting time of some of the dental materials is listed in the table below.

Material	Setting time
Fast setting alginates	1-2 minutes
Normal setting alginates	2.5 - 4 minutes
Alginate (Optimal)	3-4 minutes
Impression plaster	4 minutes

MCQs on Tooth Extraction (Exodontia) and Impactions

# All of the following statements about inhaled tooth fragment are true except:
A. It usually enters in the right bronchus
B. It may cause lung abscess
C. It may cause bronchiectasis
D. It will be coughed out spontaneously, no treatment is necessary

# Rotatory movement is used for the extraction of the :
A. Mandibular canine
B. Maxillary central incisor
C. Maxillary lateral incisor
D. All of the above

Important Signs in Clinical Medicine and their Significance : Murphy's Sign, Auspitz's sign, Trousseau's Sign, etc.

Important Signs and their significance

Sign	Significance
Nikolsky's sign	➤ Seen in Pemphigus, familial benign chronic pemphigus and recessive form of epidermolysis bullosa ➤ Loss of epithelium due to rubbing resulting in raw, sensitive surface
Auspitz's sign	➤ Seen in Psoriasis ➤ If the deep scales are removed, one or more tiny bleeding points are disclosed